Move Settings->Operations->Incidents from EE to CE

Summary

Contributes to #42640 (closed)

Move ErrorTracking -> Incidents partial (and its dependencies) from EE to CE

Incident view

Improvements

Moving the generic alerts endpoint feature from EE to CE requires a lot of code changes. All the required changes can be split and moved in several steps (as described here).

Risks

The users with the core tier will have access to the page, and change settings, although they won't be able to receive alerts until we move the "Alerts service" to the core.

Involved components

• Incidents partial
• OperationsController
• ProjectIncidentManagementSettings model

Optional: Intended side effects

Optional: Missing test coverage