These are not required because MySQL is not
supported anymore

Pages access level currently depends on project visibilty
which is ignored by factory, this commit fixes that

When the SQL query cache is active, the SELECT query for finding
projects to apply service templates returns the same values. This causes
an infinite loop because even though bulk INSERT queries are made, the
cached results never reflect that progress.  To fix this, we call
`Project.uncached` around the query to ensure new data is retrieved.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/63595

updated documentation for Geo

Consider the scenario:

1. The default visibility level is set to internal
2. A user attempts to create a private project within a private group

Previously this would always fail because default_value_for would
overwrite the private visibility setting, no matter what
visibility_level were specified. This was happening because
default_value_for was confused by the default value of 0 specified by
the database schema.

default_value_for attempts to assign the default value in the block by
checking whether the attribute has changed. The problem is that since
the default value by the database was 0, and the user requested 0, this
appeared as though no changes were made. As a result, default_value_for
would always overwrite the user's preference.

To fix this, we remove the use of default_value_for and only set the
visibility level to the default application setting when no preference
has been given at creation time.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/63158

Enable Get and Update of ci_default_git_depth for
Project API.

Renaming Project#default_git_depth to :ci_default_git_depth
to give more context through the API usage.

Add API documentation

If the origin project has no default_git_depth set (i.e. nil) set the
fork's default_git_depth to 0

Introduce default_git_depth in project's CI/CD settings and set it to
50. Use it if there is no GIT_DEPTH variable specified. Apply this
default only to newly created projects and keep it nil for old ones
in order to not break pipelines that rely on non-shallow clones.

default_git_depth can be updated from CI/CD Settings in the UI, must be
either nil or integer between 0 and 1000 (incl).

Inherit default_git_depth from the origin project when forking projects.

MR pipelines are run on a MR ref (refs/merge-requests/:iid/merge) and it
contains unique commit (i.e. merge commit) which doesn't exist in the
other branch/tags refs. We need to add it cause otherwise it may break
pipelines for old projects that have already enabled Pipelines for merge
results and have git depth 0.

Document new default_git_depth project CI/CD setting

Delete Todos for guest users when project visibility
level is updated to private.