feat: show "edited" in message status line

[WofWca]

Closes #4694.
Depends on (hence draft):

• feat: jsonrpc: add MessageObject.is_edited chatmail/core#6560.
• Translations update.

skip-changelog because:

• We'll probably have an entry for the core upgrade. Check if it's the case prior to merging.

[nicodh]

Since core is updated now, this needs a rebase and can be reviewed.

For reviewing/testing: How can I set the isEdited state in database?

[WofWca]

I haven't tested it with a real database. If you want, you can edit messages on this branch: main...wofwca/edit-messages

[WofWca]

this needs a rebase and can be reviewed.

And a translations update is still missing

[nicodh]

I haven't tested it with a real database. If you want, you can edit messages on this branch: main...wofwca/edit-messages

Ok, the "flag" in the database is, to set the param to
L=1
c=1
(including a line break)

[nicodh]

Reviewed by reading & testing