Refactor forwarded header handling into opt-in kaya-forwarded package with trusted CIDRs

requirements-dev.txt

@@ -90,12 +90,15 @@ file:./packages/kaya-core
     # via
     #   -r requirements-dev.in
     #   kaya-cors
+    #   kaya-forwarded
     #   kaya-oidc
     #   kaya-openapi
     #   kaya-rsgi
     #   kaya-session
 file:./packages/kaya-cors
     # via -r requirements-dev.in
+file:./packages/kaya-forwarded
+    # via -r requirements-dev.in
 file:./packages/kaya-oidc
     # via -r requirements-dev.in
 file:./packages/kaya-openapi