Revert line removal

Add FE component

Move OncallSchedulesController into EE

Move OncallSchedulesController and its related files to ee namespace

Add empty state on FE side

Change on-call schedules path to /-/oncall-schedules

Add on-call schedules sidebar link

Check permissions for OncallSchedulesController

Add OncallSchedulesController to feature categories

Address reviewer feedback

Address BE code review feedback

Revert testing for translations

Update translation string

Use helper method to check for nav item

Fix failing spec

Move oncall schedules nav item to ee folder

Move on-call schedule license check to policy

Move on-call schedule feature flag and licence check into policies

No need to check EE ability in FOSS code

Check the ability of viewing the operations tab in EE only

Check sidebar operations path in EE-only