- instead of using properties
- backward compatibility has to be kept for now

https://community.atlassian.com/t5/Jira-questions/Is-it-quot-JIRA-quot-or-quot-Jira-quot/qaq-p/681163

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

DroneCI and TeamCity shared the same validations methods
on the data received. These validations were extracted
into a concern

This is a take over from a community contribution:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/20990

Skip TeamCity push event when related to branch delete

Support merge request events for TeamCity service.
Add checkbox for merge request triggers in the TeamCity
configuration page.

We are deprecating this service in favor of instance wide clusters.
Therefore we removed some code that is not anymore needed for a
readonly cluster and also we added some flags to allow for this
deprecation. These flags are to be removed in the next release when
we finally completelly remove KubernetesService.

- create tables for storing issue trackers properties
- add model and basic logic & spec

Relates to #42595.
Fixes #62661.

When Kubernetes clusters were originally built they could only
exist at the project level, and so there was logic included
that assumed there would only ever be a single Kubernetes
namespace per cluster. We now support clusters at the group
and instance level, which allows multiple namespaces.

This change consolidates various project-specific fallbacks to
generate namespaces, and hands all responsibility to the
Clusters::KubernetesNamespace model. There is now no concept of
a single namespace for a Clusters::Platforms::Kubernetes; to
retrieve a namespace a project must now be supplied in all cases.

This simplifies upcoming work to use a separate Kubernetes
namespace per project environment (instead of a namespace
per project).