Update path syntax for Express

It seems that * matches a literal * now, so we have to use a regular
expression.

Parentheses around a parameter no longer works (it causes it to match on
the parameter name literally) and I am not sure why we had it anyway as
it had no effect previously.

Matching with a leading / does not appear to work either, but we do not
need the leading / anyway since the proxy logic was changed to use the
whole path.  Consequently it will never be / anymore from what I can
tell but I left that check in just in case.  I turned it into a named
parameter as well, because that seems better.

src/node/routes/pathProxy.ts

@@ -22,7 +22,7 @@ export async function proxy(
 
   if (!(await authenticated(req))) {
     // If visiting the root (/:port only) redirect to the login page.
-    if (!req.params[0] || req.params[0] === "/") {
+    if (!req.params.path || req.params.path === "/") {
       const to = self(req)
       return redirect(req, res, "login", {
         to: to !== "/" ? to : undefined,