Add a script for hiding old ShowFast results
Add a script for hiding old ShowFast results

The script keeps the specified number of the most recent results
per release and hides everything else. It is helpful for keeping
ShowFast clean and normalized.

Here is an example of hiding Spock results for XDCR and Views:

$ env/bin/python scripts/hideslow.py --components xdcr,views --max-builds 7
[28/Mar/2017 08:30:17] INFO - Hiding: build=5.0.0-1885, metric=index_20M_initial_leto
[28/Mar/2017 08:30:17] INFO - Hiding: build=5.0.0-1885, metric=index_50M_dgm_initial_leto
[28/Mar/2017 08:30:18] INFO - Hiding: build=5.0.0-1885, metric=index_20M_incremental_leto
[28/Mar/2017 08:30:18] INFO - Hiding: build=5.0.0-1885, metric=index_50M_dgm_incremental_leto
[28/Mar/2017 08:30:18] INFO - Hiding: build=5.0.0-1885, metric=query_lat_100M_dgm_leto
[28/Mar/2017 08:30:18] INFO - Hiding: build=5.0.0-1885, metric=query_lat_20M_index_95th_leto
[28/Mar/2017 08:30:18] INFO - Hiding: build=5.0.0-1885, metric=query_lat_20M_leto
[28/Mar/2017 08:30:19] INFO - Hiding: build=5.0.0-1885, metric=query_lat_20M_basic_leto
[28/Mar/2017 08:30:19] INFO - Hiding: build=5.0.0-1885, metric=query_lat_20M_body_leto
[28/Mar/2017 08:30:19] INFO - Hiding: build=5.0.0-1885, metric=query_lat_20M_compute_leto
[28/Mar/2017 08:30:19] INFO - Hiding: build=5.0.0-1885, metric=query_lat_20M_group_by_leto
[28/Mar/2017 08:30:19] INFO - Hiding: build=5.0.0-1885, metric=query_lat_20M_multi_emits_leto
[28/Mar/2017 08:30:19] INFO - Hiding: build=5.0.0-1885, metric=query_lat_20M_range_leto
[28/Mar/2017 08:30:19] INFO - Hiding: build=5.0.0-1885, metric=query_thr_20M_leto
[28/Mar/2017 08:30:20] INFO - Hiding: build=5.0.0-2110, metric=xdcr_init_1x1_unidir_100M_fe_titan_5x5
[28/Mar/2017 08:30:20] INFO - Hiding: build=5.0.0-2110, metric=xdcr_init_1x1_unidir_100M_lww_titan_5x5
...

This script also demonstrates usage of type hints in Python 3.

Change-Id: Iccd1329248dae79a56d767520f32a22e824f0cd4
Reviewed-on: http://review.couchbase.org/75875
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Pavel Paulau <dd88eded64e90046a680e3a6c0828ceb8fe8a0e7@gmail.com>

pavel-paulau/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,pavel-paulau/perfrunner,couchbase/perfrunner,couchbase/perfrunner,pavel-paulau/perfrunner,pavel-paulau/perfrunner,couchbase/perfrunner,pavel-paulau/perfrunner