ADD: experimental search feature which queries CVs

[nocollier]

This PR uses a facet search to build a sqlite3 database of CVs from projects we support. We then enable a free text search where the proper faceted search keywords are populated behind the scenes. This search:

cat.search("cesm2* gpp historical ssp585 mon r1i1p1f1 not_a_term")

will internally query the local CV database to generate these keywords:

{
    "experiment_id": ["historical", "ssp585"],
    "frequency": "mon",
    "member_id": "r1i1p1f1",
    "source_id": ["CESM2", "CESM2-WACCM", "CESM2-FV2", "CESM2-WACCM-FV2"],
    "variable_id": "gpp",
}

which are then passed into the search like normal. Terms are case insensitive and wildcards like * or % do work. Terms that are not found in the database are skipped.

• basic functionality
• documentation page
• testing
• messaging/logging for when the database is generated

[codecov]

Codecov Report

❌ Patch coverage is 23.25581% with 33 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.79%. Comparing base (8a706a4) to head (43f10f1).
⚠️ Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
intake_esgf/cv.py	22.50%	31 Missing ⚠️
intake_esgf/catalog.py	33.33%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #147      +/-   ##
==========================================
- Coverage   79.83%   77.79%   -2.05%     
==========================================
  Files          12       13       +1     
  Lines        1488     1531      +43     
  Branches      226      230       +4     
==========================================
+ Hits         1188     1191       +3     
- Misses        232      270      +38     
- Partials       68       70       +2     

Flag	Coverage Δ
unittests	77.72% <23.25%> (-2.05%)	⬇️

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[nocollier]

Make this a function argument so that this module does not depend on intake_esgf at all.

[nocollier]

Closed in favor of #153