istio/authservice: use extauthz custom action

Package Owner Merge Request

Package Changes

Envoyfilters for the authservice are replaced with authz CUSTOM action. Users are able to protect their applications on ingressgateway level by using 'protect:keycloak' label.

https://repo1.dso.mil/platform-one/big-bang/apps/core/istio-controlplane/-/merge_requests/71

https://repo1.dso.mil/platform-one/big-bang/apps/core/istio-controlplane/-/releases/1.10.4-bb.2

https://repo1.dso.mil/platform-one/big-bang/apps/core/authservice/-/merge_requests/43

https://repo1.dso.mil/platform-one/big-bang/apps/core/authservice/-/releases/0.4.0-bb.16

Additional Details

Users are still expected to list each application in authservice chains. The global client ID can be used for the ingressgateway.

Closes #658 (closed)