Parts search view

Created 2 indexes, one that has Parts that reference Variations, and the other that has Variations that reference Parts, to test how the views can be configured.

Listing Variations seems to work better, but can't list orphaned Parts.

https://www.retrograde.bike/parts

https://www.retrograde.bike/variations

Add facet filters and configure BEF.

Search Index

1. Install Search API and the Database backend modules.
2. Configure the server and create an index.
3. Include Content and Part entities.
4. Add Fields.
5. Enable all processors.

Using Views Table Rowspan to combine duplicate column values.