[api] fix review accept that aren't found (gives 500 now)
[api] remove tons of code from the status/bsrequest route

It never really worked for tons of cases to check the file dependencies
within the build service. So now osc downloads the build results and does
a local check. Much more reliable
[backend] support for dumpstate and dropbadhosts in bs_dispatch
[backend] allow to disable syncing of kiwi trees in BSConfig