Move html to haml file instead of JS

This refactors the Markdown pipeline so it supports the rendering of
multiple documents that may belong to different projects. An example of
where this happens is when displaying the event feed of a group. In this
case we retrieve events for all projects in the group. Previously we
would group events per project and render these chunks separately, but
this would result in many SQL queries being executed. By extending the
Markdown pipeline to support this out of the box we can drastically
reduce the number of SQL queries.

To achieve this we introduce a new object to the pipeline:
Banzai::RenderContext. This object simply wraps two other objects: an
optional Project instance, and an optional User instance. On its own
this wouldn't be very helpful, but a RenderContext can also be used to
associate HTML documents with specific Project instances. This work is
done in Banzai::ObjectRenderer and allows us to reuse as many queries
(and results) as possible.

In Rails 5.0 the `ActiveRecord::Inheritance::subclass_from_attributes`
method was updated.
Now it calls the `find_sti_class` method [1] which is overriden in the `Event`
model and returns needed class (`Event` vs `PushEvent`).

[1]: https://github.com/rails/rails/blob/5-0-stable/activerecord/lib/active_record/inheritance.rb#L209

This commit fixes the errors like
```
143) User#contributed_projects doesn't include IDs for unrelated projects
      Failure/Error: action = attrs.with_indifferent_access[inheritance_column].to_i

      NoMethodError:
        undefined method `with_indifferent_access' for nil:NilClass
      # ./app/models/event.rb:118:in `subclass_from_attributes'
```
which are raised on the `RAILS5=1 rspec ...` command.

The `RAILS5=1 rspec spec/controllers/admin/application_settings_controller_spec.rb`
command throws the error:

Failures:

  1) Admin::ApplicationSettingsController PUT #update falls back to defaults when settings are omitted
      Failure/Error: import_sources = params[:application_setting][:import_sources]

      NoMethodError:
        undefined method `[]' for nil:NilClass
      # ./app/controllers/admin/application_settings_controller.rb:62:in `application_setting_params'

This commit fixes it.

This reverts merge request !17730

This removes the extra check for project-ids which is not needed at all.
This does not necessarily reduce execution time of the query, but
improves planning time by a few millseconds.

Closes #37125.

Goldiloader is great, but has several issues with has_many :through relations:

* https://github.com/salsify/goldiloader/issues/12
* https://github.com/salsify/goldiloader/issues/14
* https://github.com/salsify/goldiloader/issues/18

Rather than try to figure out which applies in each case, we should just do the
drudge work of manually disabling autoloading for all relations of this type. We
can always use regular preloading for specific cases, but this way we avoid
generating invalid queries through Goldiloader's magic.

Goldiloader (https://github.com/salsify/goldiloader) can eager load
associations automatically. This removes the need for adding "includes"
calls in a variety of different places. This also comes with the added
benefit of not having to eager load data if it's not used.

Use project_authorizations instead of members to calculate manageable CI projects to speed up query (#41981)

The legacy endpoint requires no reference and defaults to the root
ref.

Closes #45154

An untested code path was triggering an Exception because Fixnum
doesn't have `one?` implemented in Rails, while arrays and collections
do.

Closes #45152

In Rails 5.0 the `ActiveRecord::ConnectionAdapters::Column::TRUE_VALUES`
constant has been removed [1] and the remaining `FALSE_VALUES` constant
has been moved to `ActiveModel::Type::Boolean` [2]

[1]: https://github.com/rails/rails/commit/a502703c3d2151d4d3b421b29fefdac5ad05df61
[2]: https://github.com/rails/rails/commit/9cc8c6f3730df3d94c81a55be9ee1b7b4ffd29f6

The TIMESTAMP data type is used for values that contain both date and
time parts. TIMESTAMP has a range of '1970-01-01 00:00:01' UTC to
'2038-01-19 03:14:07' UTC.

A Forever lib class was included to handle future dates for PostgreSQL
and MySQL, also changes were made to DeployToken to enforce Forever.date

Also removes extra conditional from JwtController