Integrate with oathkeeper via forward-auth interface (#275)

* feat: add forward-auth relation
* feat: add experimental flag
* test: add e2e tests for iap

config.yaml

@@ -2,6 +2,12 @@
 # See LICENSE file for licensing details.
 
 options:
+  enable_experimental_forward_auth:
+    description: |
+      Enables `forward-auth` middleware capabilities required to set up Identity and Access Proxy.
+      This feature is experimental and may be unstable.
+    type: boolean
+    default: False
   external_hostname:
     description: |
       The DNS name to be used by Traefik ingress.

lib/charms/harness_extensions/v0/capture_events.py

@@ -83,4 +83,3 @@ def capture(charm: CharmBase, typ_: Type[_T] = EventBase) -> Iterator[Captured[_
     event = captured[0]
     assert isinstance(event, typ_), f"expected {typ_}, not {type(event)}"
     result.event = event
-