HUE-1475 [core] Switch back from spawning server

- Remove Spawning
- Remove eventlet
- Remove greenlet
- Remove django moxy
- Remove shell application
HUE-1496 [sqoop2] Spinner showing when can't connect
[core] More obvious debugging settings
[core] Remove some Java dependencies

Keep plugin as is for now as no real need to optimize its build.
HUE-1460 [beeswax] Support non acii char in the editor
HUE-1495 [beeswax] Use operation handle for async queries

Default is blocking, so just use blocking=false in the configOverlay
of the query since it is now supported.
[sqoop2] Fix databind errors when saving and running first job and connection

When a user performs the following steps, the app would have databind errors:
1. Delete all connections and jobs, then refresh the page.
2. Create a new connection with an error, then rectify the error, then save the connection.
3. Create a new job with an error, then rectify the error, then save and run the job.

There is a moment when switching between the job that was being edited and the newly loaded
job that would cause those errors. Also, needed to make sure "isLoading" is set when fetching
new jobs and connections.