[Request] Quick search to add new node

[megalon]

Currently you can only add new nodes from the right-click menu, or copy / pasting existing nodes.

I think adding a new node should work like this:

1. Press space to open search bar (if no nodes or input fields are selected)
2. Start typing name of node. While typing a list of all node names appears, and gets shorter as you specify
3. Use up/down arrow keys to select node you want from list (if only one is found, that is auto selected)
4. Press enter to create node at mouse position