Support web UI

[nakabonne]

The pbgopy server is just an HTTP server, hence the client does not have to be a pbgopy command.

It would be nice to provide a simple web UI so that data can be shared even in environments where it is tough to install the pbgopy command, such as mobile devices. A page as simple as piping-server is ideal:

[faithfulnessalamu]

This interests me. Please correct me if I'm wrong but when you say

a page as simple as piping-server

you are referring to this UI yeah?

[nakabonne]

Eventually we want to offer something that rich, but we want something as simple as this for the first one.
See more: https://dev.to/nwtgck/data-streaming-with-every-device-over-httphttps-mo4

All we need to do is to send a request to the root path / and fix it to return a static page.

[nakabonne]

Currently, we use the root path for handling the clipboard, so we first have to change it to /clipboard.

pbgopy/commands/serve.go

Line 74 in b77c9c2

mux.HandleFunc(rootPath, r.handle)

[faithfulnessalamu]

I'll make a PR changing the clipboard endpoint first

[nakabonne]

Yes, please.

[nakabonne]

On the second thought, changing the clipboard endpoint is a significant breaking change, so it would be nice to include the change in the patch supporting Web UI.