PSK authentication is currently used between sources-superkey-worker and sources-api, in the api_client.go file from sources-superkey-worker. We need to introduce OIDC authentication as an alternative to PSK.

Acceptance criteria:

• If not already existing, a service account is created for sources-superkey-worker in stage and prod. This doesn't have to be done first.
• The sources-superkey-worker/ClowdApp config contain 3 new keys: OIDC_ISSUER (defaults to https://redhat.com/realms/redhat-external), OIDC_CLIENT_ID (value stored in the vault), OIDC_CLIENT_SECRET (value stored in the Vault).
• The github.com/coreos/go-oidc/v3/oidc dependency is added to sources-superkey-worker for the OIDC client implementation.
• The OIDC auth is covered by unit tests. IQE tests will have their dedicated Jira ticket