Changing the name of the added effect nodes should be possible

Currently you can only add single custom effect node because there is no way to change the name of the added nodes. User should be able to change the name of any added node.

The artificial limit of only one custom node should be removed.

All nodes need to check for name conflicts on add and ensure name uniqueness.

UI would be an edit button that is shown on hover over node section header. Clicking button would open text edit on top of the name field on the header.