Add option to filter/create compare report for specified machine/alias

I would like to create compare report just for given machine/alias.

My idea to implement that is to create additional simple "filter by machine" field and then filter results of comparison (after comparison is done), eg: here

Something like that

if key.machine != query_machine:
    continue
diffs.append(RunConfigResultsForTestDiff(key.test, key.testsuite, key.machine, result_from, result_to))

Edit, it would be useful to also filter by machine_tags