feat: Skip module updates requiring maintenance windows when not active

[c-pius]

Description

Changes proposed in this pull request:

• Implements a decorator implementing the maintenance window logic
• once it looked up the module template via it's decorated instance, it:
  • checks if a maintenance window is required
  • if so, checks if it is active
• if it is not active or an error happens, it sets an error and the template to nil
  • as a consequence, the manifest will not be updated and we continue to reconcile its current version
  • additionally, we display a message in the kyma module status
  • this is the same behavior as we have already for the version downgrade

Related issue(s)

• resolves: [Maintenance Windows] Skip module upgrades during maintenance window #2101

[lindnerby]

lgtm