Support feature filtering based on datasource

[ohltyler]

MDS integration is complete, and allows selecting particular data sources based on version compatibility (e.g., not allowing datasources below 2.18+ to be selectable). However, in addition to this, we may need further maintenance of feature discrepancies across different versions / configurations. For example, suppose we have an OSD 2.19 server running, connected to a 2.18 datasource and 2.19 datasource. And, suppose we introduce a new ingest processor in 2.19. We can toggle between the 2.18 & 2.19 datasources, but we should limit the available processors when selecting 2.18, to not show the newly-introduced processor as an option.

We should have some config/mechanism to add further filtering (feature flags?) based on the version and/or additional configuration of the selected datasource.

[saimedhi]

@ohltyler, I'll take another look, but from my initial understanding, on the workflows page, we will see all available data sources with versions 2.18 or higher, and we select one. At that point, we’ll have the data source version. In the future, if 2.18 doesn't support a feature or processor, In our plugin we can add logic near the code for displaying or using that processor to handle cases where the version is > 2.18, and if needed, what happens for versions ≤ 2.18. Does that sound right? Let me know if I’m missing something.