Threading pt 2 (of 3, likely)

Threading pt 2 (of 3, likely)

* Move database cleanup (e.g., deleting instances based on statuses) into the polling loop
* Rework how unit testing works with the polling loop; prior, exceptions were being thrown silently from the thread but not printed. The polling thread has now been paramaterized with override functions for the purposes of testing
* Make type cleanup more efficient since we know exactly what instances were touched, and it's inefficient to iterate over all instances if they were not
* Bump rmr-python version, and bump rmr version
* Still an item left to do in this work; refactor the thread slightly to tie in a healthcheck with a1s healthcheck. We need k8s to restart a1 if that thread dies too.

Change-Id: Ia7c4f29c9fd4de4287f17ec0d88c6129a06a5a87
Signed-off-by: Tommy Carpenter <tc677g@att.com>