Remove empty migration dir, is referenced as separate tool in docs

refs #6481
RPMs: Do not install the agent parts

refs #6481
Move agent files to contrib/ for now

refs #6481
Move dev/ to tools/docker

refs #6481
Remove sphinx/pandoc, ship markdown docs only

refs #6481
refs #5774
Correct wrong file move

refs #6481
update icinga2.8 man page

refs #6482
Add man pages for installed scripts

fixes #6482
Clean pki/ install

refs #6481
Add man pages to packages

refs #6482