[BUGFIX] Allow clipboard APIs on HTTP

[GenericStudent]

Resolves redmine ticket: 12258

Added more JS logic to allow for browsers who wont allow access to navigator.clipboard API to still copy public keys for tunnels, peers list and tunnel edit.

Works on HTTP admin access as a fallback, still attempts the modern API first

[rcmcdonald91]

There is a simpler way of facilitating copy/paste:

$('#copypubkey').click(function () {
  $('#publickey').focus();
  $('#publickey').select();
  document.execCommand("copy");
});

I don't believe this requires TLS.