Add generic oauth support

[mingfang]

Currently Kamu supports Github oauth.

kamu-node/src/app/api-server/src/app.rs

Line 437 in 679029a

AuthProviderConfig::Github(github_config) => {

We use Keycloak and it support generic oauth.

[sergiimk]

Indeed it would be great to provide a generic authN mechanism.

I guess we'll need to integrate OAuth2 along with some generic identity layer like OIDC, as we'll want to get at least an email of the user to send pipeline notifications to. Keycloak seems to support OIDC.

Would need to find a cheap way to e2e test this flow as well.

Will try to incorporate this into our roadmap.

[mingfang]

maybe we can use the Keycloak Testcontainer
https://testcontainers.com/modules/keycloak/