Add ability to change SUT in graphs

[soyacz]

Currently when sending results sut_timestamp (basically, x axis on graphs, datetime) is defined by client or automatically set to Scylla version if not provided.
There are cases when we would like to see graphs from different package perspective - e.g. how results change across driver versions, tool version or just test run time.

Allow user to select package perspective that is observed on graphs.

[soyacz]

It might be large as we there's possibility of need to change model (due to performance constraints where each point would require to query run data for packages details).