fix: persist Applications instead of deleting and Remove applications

[steinerkelvin]

Applications that are resolved (accepted/rejected) or expired will be
persisted in the chain state instead of being deleted to persist the changes
on the ledger and improve the consumption workflow of this data.

Also, now proposals can be used to remove a key from the whitelist.

Pull Request Checklist

Before submitting this PR, please make sure:

• You have run cargo clippy and addressed any warnings
• You have added appropriate tests (if applicable)
• You have updated the documentation (if applicable)
• You have reviewed your own code
• You have updated changelog (if applicable)

Related Issues

#34

[linear]

CHAIN-37 persist resolver Applications