Request Authentication Configurator

A charm configurator to have `RequestAuthentication.security.istio.io` custom resources created

A charm configurator to have RequestAuthentication.security.istio.io custom resources created.

This charm exposes a config option to define the desired claim-to-header mapping for JWT tokens validated by RequestAuthentications, integrates with Hydra to obtain the JWT issuer of employed identities, and integrates with two separate Istio charms managing K8s Gateways to have them create a RequestAuthentication each, attached to the respective K8s Gateway, one for UI-based access and the other for programmatic-based access, both sharing the collected JWT issuer and claim-to-header mapping.

This charm encompasses the common logic to have such custom RequestAuthentications set up so that it can be reused for different product solutions and easily maintained in a unified place.

This charm meets the need of having two different RequestAuthentications targeting two separate K8s Gateways when sharing all other fields, including JWT issuer and claim-to-header mapping.