Using a plugin with full github/gitlab repo URL should resolve to a correct path

[dtomvan]

As stated in https://github.com/dtomvan/xpm.xplr/blob/a4a4b1e76cc78f4643208bdf218c035aa1bbaa2a/README.md?plain=1#L47 you should be able to use full URL's like https://github.com/sayanarijit/dragon.xplr and still have them clone to ~/.local/share/xplr/sayanarijit/dragon.xplr. This is not the case. The actual path right now is ~/.local/share/xplr/github.com/sayanarijit/dragon.xplr. This way those plugins won't work as xpm assumes other paths when calling the setup function.

We should either:

1. Clone all github repos to the ~/.local/share/xplr/github.com/abc/xyz.xplr path to avoid conflicts with other git hosts (which would raise more package.path shenanigans, probably)
2. Remove the github.com prefix as well

Current workaround: just don't include full URLS for plugins hosted on GitHub. Until fixed we cannot use plugins from Gitlab etc though.

Please let me know which you prefer, or if you have some other suggestions feedback.

Ref: #7