Multi-family analyses

[Madelinehazel]

We would like to be able to run multi-family analyses.
To do so, we would need to change:

• The requirement for there to be one family ID in the analysis request
• Setting the family codename to the first element in the list (rather, some combination of the set of family codenames?)
• BUG: On the frontend, it is currently not possible to select multiple families for an analysis if you have to search for families on different pages (e.g. 2060 and 1954); if you select the datasets for the first family, and then search for the datasets for the second family, the selection for the first family disappears.

[kevinlul]

Source of bug: with remote data and custom pagination, previous search results and pages are discarded: mbrn/material-table#1921
Solution: implement ourselves like in the issue a way of keeping track of selections across pages and search results, or support some kind of OR query in the filters so everything you might want to select can be contained in one search page.