toollabs: install p7zip-full on exec nodes

"< danilo> hi, I need to run a script that uses 7z,
7z is installed in tools-login but not in tools-exec-* instances,
can someone install 7z in exec instances?"

so we already install "p7zip" but not "p7zip-full" while
if you look at dev_environ.pp we install p7zip-full there already

the difference is that the -full variety supports more compression
formats, namely 7z and 7za vs. only 7zr

let people have 7z on exec nodes as well:

"<danilo> I'm using https://github.com/halfak/Mediawiki-Utilities
to make a search in dumps, and it uses 7z for to decompress de dump"

- add to exec environment
- remove from dev environment which is now redundant and would
  cause a puppet conflict as pointed out by Yuvi on PS1

Change-Id: I841e1b1fd2cae7a01da1e8585f873ed168e96494