[Maintenance Windows] Investigate maintenance window testing approach

[c-pius]

Description

Split out of #2101

There needs to be an e2e test that verifies the module lifecycle when downtime is required. As it appears non-trivial to setup a test environment for the time-sensitive maintenance window, it should be investigated first how this can be done in e2e tests. E.g., can we arbitrarly modify the system clock so that we can easily alternate between being within our outside a maintenance window?

See #2101 for cases that need to be covered by the test.

AC

• proposed concept how to create such E2E test
• updated the AC in [Maintenance Windows] Skip module upgrades during maintenance window #2101 accordingly to implement this test

[c-pius]

May also be an option to keep that separate and don't test the transition in a single test:

• one test verifying that no update is done given no maintenance window
• one test verifying that update is done given a maintenance windows