* updates api client vars to snake_case for custom messages
* updates api client vars to snake_case for tools
* updates api client vars to snake_case for sync
* updates api client vars to snake_case for secrets engine
* updates api client vars to snake_case for auth
* updates api client vars to snake_case for usage
* updates api client dep to point to gh repo
* fixes custom-messages service unit tests
* fixes configure-ssh test
* fixes configure-ssh test...again
* updates auth method list and config views to use api service
* adds capabilities checks to auth methods route
* fixes auth method config tests
* updates SecretsEngine type to Mount
* updates listingVisibility value in config test
* adds missing copyright header