Index a defined set of topics under "Indigenous Studies" to boost their visibility

[kelynch]

Related to #595

Index topics in this list to be discoverable under the "Indigenous Studies" keyword search to boost their visibility.

Example: This search for "Kootenai language" with "Subject (Browse)" selected from the search dropdown should be discoverable under the term "Indigenous Studies" searched from the keyword dropdown.

This will build on #595 and may require a one-to-many term mapping, depending on the approach to #595.

ACCEPTANCE CRITERIA

• [x] Bibdata has a list of terms that trigger the addition of "Indigenous Studies"
• [x] At index time, this term gets added to lc_subject_facet, lc_subject_display, and subject search fields
• [x] I can search for "Indigenous Studies" in the "Subject (Keyword)" drop down and retrieve these records
• [x] I can use the "Subject > Topic" facet to limit to "Indigenous Studies" and retrieve these records
• [x] Add a flag CHANGE_THE_SUBJECT. If there is this env variable then this code will change.
• [x] Test this in staging

[minjiec]

Background information of the 2400~ terms in the spreadsheet:

• The terms are extracted from the LCSH database
• are about "the indigenous peoples of the Western Hemisphere, including Eskimos"
• but restricted to those organized hierarchically under the umbrella heading "Indians"
• and go only two levels deep.

Related projects:

1. A count of how many titles PUL has for each subject heading (left-match) as of August 2021
2. A Cotsen project that adds 650 #0 Indians to every record identified as being related to the topic of Indians, for easy retrieval