pybind/mgr/pg_autoscaler: Added autoscale-profile feature

pybind/mgr/pg_autoscaler: Added autoscale-profile feature

The autoscaler by default will start out each pool with minimal
pgs and `scale-up` the pgs when there is more usage in each pool.

Users can now use the commands:

`osd pool set autoscale-profile scale-down` to make the pools
start out with a full complement of pgs and only `scale-down`
when usage ratio across the pools are not even.

`osd pool set autoscale-profile scale-up` (by default) to make the pools
start out with minimal pgs and `scale-up` the pgs when there
is more usage in each pool.

Edited KVMonitor.cc file to make the `autoscale_profile` variable
persistent.

Edited tests/test_cal_final_pg_target.py so that it takes into account
the new `profile` argument when calling cal_final_pg_target(). Also,
added some new test cases for when profile is `scale-up`

Renamed tests/test_autoscaler.py to a more appropriate name:
tests/test_cal_ratio.py

Signed-off-by: Kamoltat <ksirivad@redhat.com>