Score set summary statistics

[afrubin]

Now that datasets are switching over to MAVE-HGVS, which can more be easily turned into data objects and analyzed, we should think about adding some basic summary statistics to each score set page. These would not be quality metrics per se, but would give users some additional insights into each datasets.

These could either be included as part of a new visualization/exploration pane (nicer), or just calculated and baked into the text on the page (easier).

Items we could add include:

• Total number of variants
• Number or proportion of single mutants, double mutants, or triple+ mutants
• Number or proportion of synonymous, missense, and nonsense variants
• Target length
• Average number of mutations per position

There's a potential benefit to exposing these via API as well, and allowing users to retrieve datasets based on these values.

[samgelman]

It would be great to be able to filter and sort datasets based on these properties!