This reverts merge request !20679

This adds a database migration that creates routes for any projects and
namespaces that don't already have one. We also remove the runtime code
for dynamically creating routes, as this is no longer necessary.

We also try to unify the way we setup OmniAuth, and how we check
if it's enabled or not.

  * Fix broken breadcrumb when switching tabs in admin/user

Closes #47419

Signed-off-by: Tao Wang <twang2218@gmail.com>

Signed-off-by: Tao Wang <twang2218@gmail.com>

Signed-off-by: Tao Wang <twang2218@gmail.com>

See https://gitlab.com/gitlab-org/gitlab-ce/issues/47677 for more information

Signed-off-by: Rémy Coutable <remy@rymai.me>

Closes #47648

When a user checks the `accept` checkbox, we will track that
acceptance as usual. That way they don't need to accept again after
they complete the registration.

When an unauthenticated user visits the `/-/users/terms` page, there
is no button to accept, decline or continue. The 'current-user menu'
is also hidden from the top bar.

Signed-off-by: Rémy Coutable <remy@rymai.me>

the initial reason for this change was that graphicsmagick does not
support writing to ico files. this fact lead to a chain of changes:

1. use png instead of ico (browser support is good enough)
2. render the overlays on the client using the canvas API. this way we
   only need to store the original favion and generate the overlay versions
   dynamically.
   this change also enables (next step) to simplify the handling of the
   stock favicons as well, as we don't need to generate all the versions
   upfront.

this ways we can keep the `lib/gitlab/ci/status/*` classes to return the
bare favicon name as it was before.

also the favicon uploader versions are now have the same names as the
stock favicons (+ `favicon_` prefix), which makes working with the
status names easier.