Multiple data flows for loading study data

[msalihaltun]

Right now we can load study data and overlay it on nodes in three different ways:

1. From cBioPortal using StudyModal.
2. Sample data via the menu.
3. File input via the menu.

2 and 3 take a different flow through the app compared to 1 and they each take a different flow in local vs collaborative. This means duplication of a lot of code (like implementing the limit of data sets requiring duplicated checks in different places). There should be a common spot these flows all pass through so that checks can be completed in an easier way.