Add mechanism to copy configurations

[harningt]

I have a few applications / ports that need setup to a single machine and want to setup multiple hosts, however the current implementation requires I either setup a QR code to partly fill details in, or manually fill it all in multiple times.

A long-press => duplicate option would save quite a bit of time.

[jp-bennett]

I agree that the handling of configs needs a bit more polish, and this in particular is a good idea.

In the current version, this can be accomplished by editing a saved config, and just saving it under a different name. This leaves the old config intact, and creates a new config under the new name.

I'll try to refine this for the next version.