Also push the frontend flag in the clusters controller

This will allow to user the term managed? on
https://gitlab.com/gitlab-org/gitlab-ce/issues/56557. Managed? will be
used to distinct clusters that are automatically managed by GitLab

- Creates new route
- Creates new controller action
- Creates call stack:
  Clusterss::ApplciationsController calls -->
  Clusters::Applications::UpdateService calls -->
  Clusters::Applications::ScheduleUpdateService calls -->
  ClusterUpdateAppWorker calls -->
  Clusters::Applications::PatchService -->
  ClusterWaitForAppInstallationWorker

DRY req params

Adds gcp_cluster:cluster_update_app queue

Schedule_update_service is uneeded

Extract common logic to a parent class (UpdateService will need it)

Introduce new UpdateService

Fix rescue class namespace

Fix RuboCop offenses

Adds BaseService for create and update services

Remove request_handler code duplication

Fixes update command

Move update_command to ApplicationCore so all apps can use it

Adds tests for Knative update_command

Adds specs for PatchService

Raise error if update receives an unistalled app

Adds update_service spec

Fix RuboCop offense

Use subject in favor of go

Adds update endpoint specs for project namespace

Adds update endpoint specs for group namespace

Fix misspellings in app/spec comments

See merge request gitlab-org/gitlab-ce!25517

This reverts commit 9202bbd129537a698b986e6295d0c783b5a84815, reversing
changes made to 4b282e9ce1ae246c4538b3ede18d1380ea778029.

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

- Fixes multiple typos on AutoDevops script
- Add an alias to Clusters::Cluster#domain as base_domain, so it's more
descriptive
- Removes unnecessary memoization on qa specs
- Changes migration to a post migration to deal better with traffic on
big instances (like gitlab.com)

Changes domain field to be on the Cluster page show, removing it from
Auto DevOps setting. Also injects the new environment variable
KUBE_INGRESS_BASE_DOMAIN into kubernetes#predefined_variables.

Migration to move the information from ProjectAutoDevops#domain
to Clusters::Cluster#domain. As well as necessary modifications to qa
selectors

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/52363

Given the note is about how to interpret ancestor clusters, use the
finder which actually knows if there are any ancestor clusters to find
out if the note should be shown, rather than passing the same info via a
view to a helper

Added note about Kaminari.paginate_array

Link to followup issue too

Show both the cluster(s) of the clusterable, and the cluster(s) of
ancestor groups.