With executing assertEqual(expected, given) the results, especially with
dicts or multiline strings, are more readable in case of failure.

Improves 57bdf689 by having stored and
expected values stable across runs.

Also assertion is done with {hash} instead its real value, as it has no
meaning to test user.

Each slave rejected by the frontend will report back detailed information
to slave requester in key request-error-list being [json_list_of_found_errors]

Master partition reports information in rejected-slave-dict instead of
rejected-slave-list, which is defined as:

{
  'slave_name': '[json_list_of_found_errors]'
}

Globals were needed to distnc between caddy-frontend and apache-frontend.

As Age value can vary and it is not predictable, assert its existence only.

Slaves' hostnames (custom_domain or server-alias) can clash, resulting
with stopping the whole frontend.

In order to avoid so assure hostname unicity across whole frontend.

Even if the master partition owner will authorise given slave for custom
configuration reject this slave in case if it does not pass validation for
snippet.

If server alias duplicates name of the server or another alias, simply
ignore it.

Instead of relying on slapos.cookbook:certificate_authority recipe, which
stops buildout processing, extract the minimal implementation to runtime
key/certificate validator and reject slaves, which does not pass this test.

This commits results in TODO item being done.

As slave requester is able to enter any string in server-alias validate it
against being correct domain name and in case if validation fails reject that
slave.

Also use a trick to have access to global slave state, see
https://fabianlee.org/2016/10/18/saltstack-setting-a-jinja2-variable-from-an-inner-block-scope/

Install validators dependency, which is a way to easily check if email is an
email or domain is correct.

As slave requester is able to enter any string in custom domain validate it
against being correct domain name and in case if validation fails reject that
slave.

Thank to escaping whole command-line it is possible to process buildout
dangerous strings, like ${section:option}, pass them to the wrapper,
instead of killing the whole profile processing.

If the value does not contain "," drop its contents instead of stopping
processing of the whole profile.

Add plugin assertions in TestSlave.test_master_partition_state and drop
check-free-disk-space from promise directory.

As check-free-disk-space promise is implemented in plugin directory, add it
to list of assertions and drop it from promise list assertions.

Also already existing monitoring plugins are asserted.

/reviewed-on nexedi/slapos!368

As monitor stack uses values directly from buildout convert them to buildout
safe values, otherwise the the magic !py! is not stripped.

Also add a test proving that monitor with default values is going to be
correctly configured.

The backend url can come from request in `url` and `https-url` strings.
It is validated using real caddy template configuration and by using
caddy's `-stdin`. It results with calling it on each slave having any of
those parameters.

Fixes:

 * skip tests for parts which won't be fixed
 * fix assertion for master partition
 * fix typos
 * parameterize headers depending on frontend type

This reverts commit 8e24f3ab.

QUIC has issues with client certificate authentication, detected by chance.

Enables QUIC protocol https://github.com/mholt/caddy/wiki/QUIC

/reviewed-on nexedi/slapos!360