GDPR Compliance - Automate deletion of inactive users' accounts

Is your feature request related to a problem? Please describe.

GDPR states that personal data should only be kept the shortest time possible. Currently, if a user doesn't use his account (e.g. 12 months of inactivity), his data are kept forever (unless the user connects to his account and deletes it).

https://ec.europa.eu/info/law/law-topic/data-protection/reform/rules-business-and-organisations/principles-gdpr/how-long-can-data-be-kept-and-it-necessary-update-it_en

Describe the solution you'd like
Some cities are asking us for a feature to automatically delete users' accounts that haven't been used in a certain period of time. First they would receive an email asking them to connect if they want to keep their account. If they don't connect in a certain period, the account is deleted.

There is a possibility to fund the development of the feature.