RTE doesn't work if configured base url is not used

The RTE does not work if the configured base url is not used to edit a page.

For example, if you have http://localhost:8080/confluence set as your base url in general config and you access the wiki to edit a page with http://some_ip:8080/confluence, then the RTE does not load properly.

We do say in the documentation that Confluence must be accessed by the configured base url, however I believe there are a lot of instances that are setup this way anyway.

In the very least, we should show a warning message indicating that the user is trying to edit a page with a different url.