search-api endpoint enhancement: Which "entities" satisfy text searches, including regular expressions?

[AlanSimmons]

Use case 7 of #590

This is an enhancement of the endpoint for Use Case 4 described in #601.

Story

As a consumer of the search-api, I want to be able to perform simple text searches on specific attributes, including via regular expressions.

Examples:

1. Return data for all datasets from CODEX assays that were performed on tissue samples that were obtained from the small intestines of female donors with first name "Mary".
2. List all files with "XYZ" in the filename.
3. Return data for all datasets that have "snRNA" or "sn-RNA" in the description.

Target

Developers of applications that would call the API.

Technical Translation

Enhance the query for use case 4 to allow text searches--e.g., using "match" instead of "match_phrase", etc.

Solution options

Support text searches of specific attributes in endpoints.