Add a rudimentary warning to the link share dialog

[yuvipanda]

Anyone with the token has full access to your server - including all your files - until you restart your server. We must make sure users know this.

Moves the link into a textbox that autoselects on click, rather than just a link. Users don't actually want to click this - they only want to copy this. It also provides stylistic relief given we have so much more text there now.

This is how it looks now.

[jtpio]

Thanks!

[yuvipanda]

Failing check is unrelated again I think.

[yuvipanda]

Check has passed! \o/