[Tails-l10n] Icedove documentation (short notice)

Hi,

Since the RC is out I've been working on the documentation for Icedove
and the migration from Claws Mail. A good draft is available in
doc/7158-icedove. If you want to translate this in time for 1.7 (Tuesday
3) that could helpful for your user base.

To see what I'm talking about you can do:

git diff origin/testing...origin/doc/7158-icedove wiki/src/doc

These strings might change a bit again before the release after they get
reviewed but probably not that much.

And yes, I'm very sorry for the short notice.