Improve analysis joins performance in Builder UI

[elenatorro]

Related issue: https://github.com/CartoDB/support/issues/2291

Acceptance steps

1. Create a new user in staging
2. Add +70 datasets
3. Create a map from one of the datasets
4. Go to edit the map
5. Add a "Add Columns from 2nd Dataset" Analysis
6. Check how much time the target dropdown list takes to load
7. Select a target and add the analysis
8. Check the analysis works properly

[elenatorro]

I've done a second acceptance round with different geometries and it works as expected (it disables the analysis that can't be applied depending on the geometry)

In my opinion, I think we can merge it 👍

[alejandraarri]

LGTM! ✨