Backport the EE schema to CE

Closes gitlab-ee#9686

See merge request gitlab-org/gitlab-ce!26940

EE: Backport the EE schema to CE

See merge request gitlab-org/gitlab-ee!12998

CE backport for gitlab-org/gitlab-ee!14064: Add merge train position indicator

See merge request gitlab-org/gitlab-ce!29561

Add merge train position indicator

Closes #11981

See merge request gitlab-org/gitlab-ee!14064

This commit adds an informational message under the pipeline block in
the merge request widget that displays the current position of the merge
request on the merge train.

read_repository scope can be used for API

See merge request gitlab-org/gitlab-ce!29663

CE port of IP address restriction for groups

See merge request gitlab-org/gitlab-ce!29467

IP address restriction for groups

See merge request gitlab-org/gitlab-ee!12669

- policies fixed
- schema updated
- Groups::UpdateService to handle params
- form added
- validate subnet, top-level group, and group presence
- ability to combine multiple IpRestriction removed
- avoid saving previous IP address in IpAddressState
- avoid user namespaces
- specs added
- license check added

Fix list rendering on docs site

See merge request gitlab-org/gitlab-ce!29738

Translate missing string in `ci_template.js`

Closes #12220

See merge request gitlab-org/gitlab-ee!14188

One can not upgrade straigt from 9.3 to 12.0, due to the schema changes
being backported. Instead, one must first upgrade to 11.11.X. Omnibus
already enforces this, and our online upgrade guidelines also cover
this.

By changing the CI config we don't have to adjust the backport migration
to handle a migration path that one can not take.

This backports all EE schema changes to CE, including EE migrations,
ensuring both use the same schema.

== Updated tests

A spec related to ghost and support bot users had to be modified to make
it pass. The spec in question assumes that the "support_bot" column
exists when defining the spec. In the single codebase setup this is not
the case, as the column is backported in a later migration. Any attempt
to use a different schema version or use of "around" blocks to
conditionally disable specs won't help, as reverting the backport
migration would also drop the "support_bot" column. Removing the
"support_bot" tests entirely appears to be the only solution.

We also need to update some foreign key tests now that we have
backported the EE columns. Fortunately, these changes are very minor.

== Backporting migrations

This commit moves EE specific migrations (except those for the Geo
tracking database) and related files to CE, and also removes any traces
of the ee/db directory.

Some migrations had to be modified or removed, as they no longer work
with the schema being backported. These migrations were all quite old,
so we opted for removing them where modifying them would take too much
time and effort.

Some old migrations were modified in EE, while also existing in CE. In
these cases we took the EE code, and in one case removed them entirely.
It's not worth spending time trying to merge these changes somehow as we
plan to remove old migrations around the release of 12.0, see
https://gitlab.com/gitlab-org/gitlab-ce/issues/59177 for more details.

This is necessary for backporting the EE schema to ensure backported
foreign keys use the same key names.

One can not upgrade straigt from 9.3 to 12.0, due to the schema changes
being backported. Instead, one must first upgrade to 11.11.X. Omnibus
already enforces this, and our online upgrade guidelines also cover
this.

By changing the CI config we don't have to adjust the backport migration
to handle a migration path that one can not take.

This backports all EE schema changes to CE, including EE migrations,
ensuring both use the same schema.

== Updated tests

A spec related to ghost and support bot users had to be modified to make
it pass. The spec in question assumes that the "support_bot" column
exists when defining the spec. In the single codebase setup this is not
the case, as the column is backported in a later migration. Any attempt
to use a different schema version or use of "around" blocks to
conditionally disable specs won't help, as reverting the backport
migration would also drop the "support_bot" column. Removing the
"support_bot" tests entirely appears to be the only solution.

We also need to update some foreign key tests now that we have
backported the EE columns. Fortunately, these changes are very minor.

== Backporting migrations

This commit moves EE specific migrations (except those for the Geo
tracking database) and related files to CE, and also removes any traces
of the ee/db directory.

Some migrations had to be modified or removed, as they no longer work
with the schema being backported. These migrations were all quite old,
so we opted for removing them where modifying them would take too much
time and effort.

Some old migrations were modified in EE, while also existing in CE. In
these cases we took the EE code, and in one case removed them entirely.
It's not worth spending time trying to merge these changes somehow as we
plan to remove old migrations around the release of 12.0, see
https://gitlab.com/gitlab-org/gitlab-ce/issues/59177 for more details.

This is necessary for backporting the EE schema to ensure backported
foreign keys use the same key names.

Create models for issue trackers data

See merge request gitlab-org/gitlab-ce!28598

Create models for issue trackers data

See merge request gitlab-org/gitlab-ee!14187

Docs for Web IDE file sync

See merge request gitlab-org/gitlab-ce!29638

Docs for Merge Trains

See merge request gitlab-org/gitlab-ce!29047

This commit adds an informational message under the pipeline block in
the merge request widget that displays the current position of the merge
request on the merge train.

And regenerate `gitlab.pot`

Fix GPG signature verification with recent versions of GnuPG

Closes #58747

See merge request gitlab-org/gitlab-ce!29388

Resolve "Display and logic improvements for cycle analytics"

Closes #30138

See merge request gitlab-org/gitlab-ce!29018

Fix plan stage query and the way it is displayed

EE backport for Resolve "Display and logic improvements for cycle analytics"

See merge request gitlab-org/gitlab-ee!14143

Work around missing pagination headers

See merge request gitlab-org/gitlab-ee!14142