Ability to automaticly delete attachments after some time to save provider space

[g6094199]

Related/enhancement to

Expected behavior

@g6094199

Thunderbird an other email programs have the ability to remove/detach attachments (images, files, etc) from a message. Maybe we can choose also for locally or on the server?
This would be handy for DS, too.

There are several situations that would benefit here:

• You want to keep the message but you want to get rid of the “garbage” attached
• You have an email provider that strictly limits the amount of used space (e.g. web.de: 1GB). Manualy deleting messages via autocrypt/enigmail plugin for TB is a pain in the arse when you want to select what to keep…
• You have limited resources on your mobile phone
• …whatever you think of…

In any case you can keep more messages.

The additional idea here is the ability to set vanishing time for attachments (6M, 1Y, etc) so you will save a lot of space in you email postbox.
additionally we have so more granulated control like:

• set the message size to delete (greater then)
• choosing the type of attachment to delete (file, audio, media)
• of cause setting the past time (6M, 1Y, etc)
• …

Actual behavior

delete ALL messages automatically after some time or delete a message manually