Add autocompletion to subflows

[anna-geller]

Currently, when adding a subflow, you need to know the namespace, flowId and inputs properties of a subflow.

It would be a great improvement to the UX if kestra would provide autocompletion. E.g.:

1. after you've specified the namespace, you get autocompletion on the flowId property based on flows available in that namespace.
2. after you've set the flowId, the inputs map property can give autocompletion of available input properties

Update as of 16.04.2024

1. Autocompletion for subflows (autocomplete namespace name first, then autocomplete the flow ID)
2. Add a link to the subflow flow code in the Editor under the flow ID, allowing users to edit the flow in the same Flow Editor (new Editor tab, not a browser tab → it’s important for Ludo that it's in the same Editor, not a new browser tab). See example to clarify: