f6c2a23 backend: add a convenience globals

Authored and Committed by praiskup 2 years ago
    backend: add a convenience globals
    
    Those globals are making our life easier becase now we can just stuff
    like:
    
      from copr_backend.setup import app, config, log
      app.redirect_to_redis_log("actions")  # creates actions.log
      log.info("results are in %s", config.destdir)
    
    So all the heavy-lifting related to redis logging, backend config
    parsing, etc. is now for free.  This is similar concept used by Flask on
    the Frontend side.