Handle drafts like signal-android

[smichel17]

• I have searched open and closed issues for duplicates

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Description

Signal-android handles drafts really well, and I miss its behavior on the desktop app. Two parts:

1. Persist drafts across application restart
2. Sort conversations with drafts by the timestamp of the most recent draft edit
   2a. Show the draft contents in the preview

Steps to reproduce

1. • Compose a draft to contact or group X
   • Close Signal without deleting the draft
   • Open Signal
   • Switch back to X
     Actual result: Composition box is empty
     Expected result: Composition box is still filled in with draft
2. • Compose a draft to contact or group X
   • Switch to a different conversation without deleting the draft
     Actual results: X stays in its previous sorted position.
     2a. The preview displays the last recieved/sent message
     Expected results: X is sorted to the top of the list.
     2a. The preview displays: Draft: a few words from the draft...

[craywolf]

+1 for the above, and also:

Syncing drafts between Desktop and Mobile would be convenient as well. Telegram does this and, while I wouldn't call it critical functionality, it's handy.

[mammuth]

Syncing drafts between Desktop and Mobile would be convenient as well.

There is a separate issue for synching drafts: #702

[denver-s]

Drafts are now preserved when closing Signal. This issue can be closed.

[smichel17]

So they are!