Rename project-level integrations routes and `Projects::ServicesController` from services to integrations

About

We want to rename the project-level integration routes (-/<project-full-path>/services) and the corresponding Projects::ServicesController controller from services to integrations.

This change involves updating the regexes needed to support these files in tooling/danger/project_helper.rb !74330 (merged).

We also want to rename the views in app/views/projects/services (but not the custom integration templates in the same folder, which should be moved into app/views/shared/integrations instead) #353379 (closed).

Notes:

• We do not want to rename the instance-level Admin::ServicesController and routes and these are for a deprecated feature called "integration templates".
• Route changes are sometimes subject to deprecation requirements, however these routes are considered Limited use, unlikely to be shared, so we can make a "breaking" change.

Testing & Availability

Suggestion: update any tests to reflect the changes in routes, this will likely include some QA tests as well. See qa/qa/page/project/settings/services/prometheus.rb

Rollout

• Rename controller and related files: !88043 (merged)
• Remove legacy /-/integrations routes in %15.2: !90634 (merged)