[backend] remove $conf as payload for SRCSRV_START

No notification plugin can handle perl code as type, nor is it supposed
to handle it. I wonder who is interested in this event anyway
[api] also allow render exceptions in JSON routes
[backend] remove old request handling

Only leaving the functions needed to run the 2.4 API migrations
[api] remove some files not needed anymore
[api] fix structure.sql
[webui] fix spider test suite
[api] remove code duplication in comments controller (and remove tabs)
[backend] fix last archlinux publisher change

simply replacing symlink with link is not enough...
[backend] no longer send SRCSRV_START notification

It no longer has a valid payload and as such rather spam (and we couldn't
come up with a valid use case)
[api] remove unused production_test environment

(was never even ported to rails 3)
[api] move the actual auto accept out of the clock daemon

The clock daemon stops while doing jobs, so everything that takes
longer than a couple of milliseconds should only trigger a delayed
job

While I was at it, I moved the rather huge and clumpsy BsRequest.collection
function into a model on its own (to be further refactored)
[api] refactor BsRequestCollection further
[webui] remove unused code
[dist] fix spec file list after production_test got removed
[backend] chase pubkey2sslcert argument change done in commit #04a23ca2

Makes cert generation work again.
[backend] implement product description parsing for source server
[api] basic product tracking
[api] find patchinfo packages by package kind and not via package name convention
[api] basic channel tracking
[api] add "addchannels" api call, which does copy matching channel packages and repositories