GraphQL - Authenticate without JWT for Introspection

[rccoe]

Is your feature request related to a problem? Please describe.
Problem: Want to enable machine-to-machine introspection of the CubeJS GraphQL generated API. Currently you must authenticate via JWT

Describe the solution you'd like
Allow for another way to authenticate with cubeJS to get the /meta data for the API

Describe alternatives you've considered
checkAuth() or checkSqlAuth() look promising: https://cube.dev/docs/config#check-auth
Maybe there could be another, say checkGraphQLMetaAuth()