Add keyword search to the search form

[anandaroop]

A user should be able to enter a free-form text query.

Based on the work in https://github.com/artsy/gravity/pull/10867 let's investigate adding a free-text keyword field to the search form.

From that PR:

This adds support to the /api/v1/filter/artworks endpoint for a deeper term search across name, genes, tags, and auto_tags fields. This allows us to perform keyword queries across multiple genes/tags/auto-tags simultaneously using free-form natural language phrases - searches like 'portrait painting', 'steel sculpture', 'latin american sculpture', 'digital video' or even literal phrases like 'person on a beach' or 'painting of a child'. It won't allow artist name searches, which I suspect we'll see in the wild, but I can follow up to add this if need be.

[anandaroop]

Noting here that artist names and partner names have been added to Gravity's keyword search in https://github.com/artsy/gravity/pull/11052, so we will get those as well whenever this gets implemented 🙌