constants: Add logging format for atomic_reactor
constants: Add logging format for atomic_reactor

OSBS client will need the atomic_reactor logs in a specific format
in order to parse them correctly.  Control that in osbs-client and
make it available for atomic_reactor to import.

projectatomic/osbs-client,bfontecc007/osbs-client,DBuildService/osbs-client,projectatomic/osbs-client,vrutkovs/osbs-client,bfontecc007/osbs-client,DBuildService/osbs-client,vrutkovs/osbs-client