Rename project identity to OpenGeoMetadata

[ewlarson]

Summary

This OGM API project is extracted from the BTAA Geospatial API, with additional code to periodically harvest and ingest OGM metadata records from GitHub repositories nightly. Renaming the BTAA things here to OpenGeoMetadata equivalents.

• replace product-facing BTAA and Big Ten naming with OGM or OpenGeoMetadata across the runtime, scripts, tests, documentation, fixtures, and retained legacy code
• rename identity-bearing importers, migrations, fixture directories, and upstream-source metadata
• remove obsolete BTAA logo assets and add an automated identity check for future changes
• preserve compatibility for existing production data, API keys, upstream provenance, and deployment infrastructure

Compatibility and deployment safety

• keeps the live PostgreSQL database, populated gazetteer table, Elasticsearch index, volumes, image identity, Kamal service name, and proxy hostname unchanged
• accepts legacy fallback API-key hashes and upgrades them in place after successful authentication
• preserves real upstream repository, GIN, linked-data, asset, and fixture-provenance identifiers
• leaves config/deploy.yml and LICENSE unchanged
• does not deploy or otherwise alter the production Kamal instance

Verification

• full backend suite: 1833 passed, 99 skipped, 1 xpassed
• API-key compatibility suite: 12 passed, including legacy fallback-hash acceptance and rewrite
• make lint-check
• make identity-check
• ./scripts/verify_transfer_readiness.sh --post-transfer
• git diff --check