* Inline API Gateway TLS cert code (#16295)
* Include secret type when building resources from config snapshot
* First pass at generating envoy secrets from api-gateway snapshot
* Update comments for xDS update order
* Add secret type + corresponding golden files to existing tests
* Initialize test helpers for testing api-gateway resource generation
* Generate golden files for new api-gateway xDS resource test
* Support ADS for TLS certificates on api-gateway
* Configure TLS on api-gateway listeners
* Inline TLS cert code
* update tests
* Add SNI support so we can have multiple certificates
* Remove commented out section from helper
* regen deep-copy
* Add tcp tls test
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Co-authored-by: Nathan Coleman <nathan.coleman@hashicorp.com>
* Fix bad merge
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Co-authored-by: Andrew Stucki <andrew.stucki@hashicorp.com>
Co-authored-by: Nathan Coleman <nathan.coleman@hashicorp.com>
