proxy: remove auth info from http conn info & fixup jwt api trait (#9047)

misc changes split out from #8855 

- **allow cloning the request context in a read-only fashion for
background tasks**
- **propagate endpoint and request context through the jwk cache**
- **only allow password based auth for md5 during testing**
- **remove auth info from conn info**

test_runner/fixtures/neon_fixtures.py

@@ -3863,9 +3863,6 @@ def static_proxy(
     dbname = vanilla_pg.default_options["dbname"]
     auth_endpoint = f"postgres://proxy:password@{host}:{port}/{dbname}"
 
-    # require password for 'http_auth' user
-    vanilla_pg.edit_hba([f"host {dbname} http_auth {host} password"])
-
     # For simplicity, we use the same user for both `--auth-endpoint` and `safe_psql`
     vanilla_pg.start()
     vanilla_pg.safe_psql("create user proxy with login superuser password 'password'")