Set Thunderbird account preferences previously set by TorBirdy

Originally created by @segfault on #17222 (Redmine)

Everytime Thunderbird is started, TorBirdy overwrites some account preferences, see https://gitweb.torproject.org/torbirdy.git/tree/components/torbirdy.js#n568.

We should go through them, check whether they make sense in the context of Tails, and find a way to set those account preferences.

Feature Branch: feature/17219-replace-torbirdy

Edited May 15, 2020 by segfault

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