Upgrade icedove to 45.1.0esr

Currently version 1:45.1.0-1~deb8u1 is in Debian, which is higher than 38.8.0-1~deb8u1+tails3 from our custom APT suite. So the secure auto-configuration fixes are lost in current Tails builds.

We need to build new packages from 1:45.1.0-1~deb8u1 + our patches (which likely will need some refreshing).

Parent Task: #5663 (closed)

Original created by @anonym on 11530 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information