bugzilla module

make bugzilla stuff a module

these things are not new, they are a conversion to module from the existing ./manifests/misc/bugzilla.pp

so i'm not specifically asking for a review of the scripts so much,
but about the module structure itself.

i purposely did not make it a change that also uses the module right
away and (re-)moves the existing files. the old classes are called
misc::bugzilla while this would be just bugzilla::.

i would like to first merge the module, test it on boogz in labs and on
zirconium in eqiad and when confirmed it works switch from old Tampa
server kaulen to zirconium, also resolving RT #4783.

after that i'd remove the old misc::bugzilla classes and files and we
can shutdown kaulen

PS7: unify auditlog and communitymetrics classes into a single
     defined type as suggested by akosiaris

Change-Id: I5381a2c57b0a3483f7ac3e79639b242054ad9e6f
Merge "bugzilla module" into production