Clean up docs redirects - 2021-08-17

See merge request gitlab-org/gitlab!68334

Add security warning to group import doc

See merge request gitlab-org/gitlab!68411

Remove temporary check from SpamParams service refactor

See merge request gitlab-org/gitlab!68333

Fix Rubocop Graphql/Description offenses [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!68027

Merge branch '297366-the-banner-prompting-users-to-check-their-account-recovery-settings-causes-confusion-2' into 'master'

Update copy in recovery settings alert

See merge request gitlab-org/gitlab!68001

Migrate the deprecated "urlParamsToObject" to "queryToObject"

See merge request gitlab-org/gitlab!65920

Merge branch '331613-allow-assigning-to-the-members-of-descendant-groups-when-creating-assignee-list-on-group' into 'master'

Added ability to create assignee list of descendants

See merge request gitlab-org/gitlab!66016

Changelog: fixed

Fix markdown issue in style guide content

See merge request gitlab-org/gitlab!68327

Docs MVC of how the new Gitpod feature works

See merge request gitlab-org/gitlab!68322

Move bulk-related items down, subtle renaming

See merge request gitlab-org/gitlab!67261

Update agent creation documentation

See merge request gitlab-org/gitlab!66008

Fix inconsistencies in the Proofreaders list

See merge request gitlab-org/gitlab!67891

Change CVE ID Requests Docs page to be Threat Insights ownership

See merge request gitlab-org/gitlab!68413

Finalize conversion of ci_stages.id to bigint

See merge request gitlab-org/gitlab!66088

Do not run refresh_member_authorized_projects callback when importing

See merge request gitlab-org/gitlab!67975

Move `seats usage` from billing to usage quotas

See merge request gitlab-org/gitlab!67576

Fix reference pattern for iterations

See merge request gitlab-org/gitlab!68350

Add estimate_batch_distinct_count operation block passing support

See merge request gitlab-org/gitlab!68107

Activate semgrep for C projects

See merge request gitlab-org/gitlab!68143

Merge branch '331825-eng-record-the-experimentsubject-for-highlight-paid-feature-experiment' into 'master'

Record the ExperimentSubject for Highlight Paid Feature experiment

See merge request gitlab-org/gitlab!64037

Cleanup the "Add contact sales option in app" experiment

See merge request gitlab-org/gitlab!65598

Added issue board to word list

See merge request gitlab-org/gitlab!68387

- Remove the experiment feature flag
- Solidify the Snowplow tracking events
- Clean up the code in use
- Add & update specs accordingly

Changelog: added