feat(zap): adds keycloak for JWT and auth mgmt

Replaces the custom made auth-backend (auth-gateway) with its token logic and complexity
with established open-source FIPS 140-2 compliant authentication solution.
Current code uses newly deployed keycloak within kind deployment script,
but some todos are left and should be further developed.
Does not use auth-gateway anymore for authentication,
only as a proxy to extract authorization and user information from token for downstream apis.

solves #28