Automatically Remove Expired Certificates

[psavva]

• The request is to have expired certificates automatically purged from the Wallet.

• Display the Expiry Date on the main screen that shows all loaded certificates as to ensure the holder is aware of when the specific certificate expires.

• It also has the benefit of not holding this information (even for spouse or dependents, parents, etc.) once they expire, and thus no longer useful. This is a security consideration.

[psavva]

Same is Requested for iOS: https://github.com/eu-digital-green-certificates/dgca-wallet-app-ios/issues/76