Improve documentation on the URL to access Crucible after startup

In section 6 of the upgrade we state:

After a few moments, in a web browser on the same machine, go to http://localhost:8060/ (or, from another machine, type http://hostname:8060/ , where hostname is the name of the machine where you installed Crucible).

If a customer has changed the port Crucible is listening on in their config.xml this can cause some confusion, especially since the startup logs also have this path hard-coded instead of reading it from the configuration file: (CRUC-3590: Log the correct hostname when fisheye is starting up (fixed in Crucible N/A)

We suggest to add an info/warn panel in that section:

You may have configured Crucible to listen to a port other than the default 8060, for example
http bind=":80. In this case, please access Crucible on the configured hostname/port