Update master branch to build upstream 2.x

Updated version from upstream tag 2.0.9 (mosts of the commits are from upstream, since they weren't included in 2.0.8).

Updated copyright info and readme (from upstream info).

Removed branch 1.x patches (unnecessary) and tests (included in upstream).

Updated build dependencies, domain config getter/setter and build rules.

Added init file to fix lintian error (needs to be looked at).

I'm not a Debian developer, so It could use a code review (especially init file), but all tests pass and I'm able to install it on Trixie.