Deleting user account

[Fezzzi]

When user deletes his account:

• Clear his fs directory of all pending files
• Remove all households he is the only admin of that don't have any users of maintainer status
• Shift admin status to all maintainers otherwise
• Properly log all associated actions to activity feed
• Also provide some further hint information to all household roles to explain their abilities and meaning

Nice to have would be to mark his account as to be deleted, send an email with a link to perform deleting instanteniously, and wait for a month otherwise and delete only if the user didn't log in in the meantime. On attempt to log in then display a pop-up saying the account is scheduled for deletion on x.y.zzzz and give an option to abort deletion.