Suggestion: Allow conquered towns to leave a nation after a period of time

[HippieBeak]

Is your feature request related to a problem? Please describe.
Some towns repeatedly lose their revolt siege, or do not have the funds to siege. This frustrates the conquered town, as they feel trapped with no way out - especially if they were conquered by a powerful nation.

Describe the solution you'd like
I would like to add a config option that allows towns to /n leave after some period of time. Perhaps also require them to revolt siege at least x times before they can /n leave

Describe alternatives you've considered
N/A

Additional context
N/A