feat(action v2): add JWT and JWE payload type options (#11196)

# Which Problems Are Solved

The payload in actions V2 is currently sent as JSON to the target
endpoint. It might get exposed to intermediary infrastructure or logging
systems.
For these scenarios there needs to be an application-layer encryption,
where the provider of the endpoint can define an key to be used for the
encryption.

# How the Problems Are Solved

- Added an additional option to the target to specify the payload type:
`JSON` (current and default), `JWT`, `JWE` (api and console)
- added endpoints to upload and manage public keys (to be used for
encryption) for a target
- updated all action v2 executions (interceptors, oidc, saml, ...) to
provide the `GetActiveSigningWebKey` from queries
- implemented jwt and jwe in the exections incl. refactoring of code and
tests
- changes to the authn_keys table:
  - added a `fingerprint` column
  - dropped not null constraint on expiration
- moved the `GetSignerOnce` into its own package to prevent circular
dependencies

# Additional Changes

None

# Additional Context

closes #11061

---------

Co-authored-by: Marco A. <[email protected]>
Co-authored-by: conblem <[email protected]>
Co-authored-by: Silvan <[email protected]>

internal/query/instance_by_id.sql

@@ -26,7 +26,10 @@ with features as (
 			'endpoint', t.endpoint,
 			'timeout', t.timeout,
 			'interrupt_on_error', t.interrupt_on_error,
-			'signing_key', t.signing_key
+			'signing_key', t.signing_key,
+            'payload_type', t.payload_type,
+            'encryption_key', encode(k.public_key, 'base64'),
+            'encryption_key_id', k.id
 		) as execution_targets
 		from projections.executions1 e
 		join projections.executions1_targets et
@@ -35,6 +38,11 @@ with features as (
 		join projections.targets2 t
 			on et.instance_id = t.instance_id
 			and et.target_id = t.id
+        left join projections.authn_keys2 k
+            on k.instance_id = et.instance_id
+            and k.object_id = t.id
+            and k.enabled = true
+            and (k.expiration IS NULL or k.expiration > now())
 		where e.instance_id = $1
 		order by et.position asc
 	) as x