usr.bin.thunderbird: refresh profile from Debian Stretch
* Add Xubuntu helpers to launch the browser
* Grant access to commonly used locations (for attachments)
* Add new proc/sys files required for newer version of Thunderbird
* Support accessing icedove directories for smoth transition
* Unify gpg2 and gpg subprofiles
* Add lsb_release subprofile
Evolution: drop support for obsolete /dev/.udev/ directory.
Michael Biebl, one on the systemd/udev maintainers in Debian, wrote https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=846966#50: "This directory
has long been deprecated and is not in use anymore since at least jessie, might
even be wheezy".