Extract session directive in a dedicated package

Signed-off-by: Bryan Frimin <bryan@getprobo.com>

pkg/server/api/connect/v1/gqlgen.yaml

@@ -1,4 +1,4 @@
-schema: ["schema.graphql"]
+schema: ["schema.graphql", "../../gqlutils/directives/session/schema.graphql"]
 
 exec:
   filename: "schema/schema.go"
@@ -20,6 +20,8 @@ call_argument_directives_with_null: true
 directives:
   mustBeAuthorized:
     skip_runtime: false
+  session:
+    skip_runtime: false
 
 models:
   ID: