Improve non base URL (base-url) handling

In some edge cases, customers would want to access their Jira on non base URL.
Even though it's a must that Jira should be accessed on base URL only https://confluence.atlassian.com/adminjiraserver0912/configuring-the-base-url-1346048133.html it would be great if Jira was able to differentiate or dynamically change the base URL based on the URL that it's being accessed from a browser, rather than the one configured as the base URL in Jira itself

It would allow such configurations where instead of load balancing customer could use URL redirects instead.

I.e for example if customer has a load balancer with URL1 and 4 nodes behind that load balancer (URL2, URL3, URL4, URL5), if all that load balancer does is redirects the traffic to the 4 nodes - the idea is that Jira should be able to handle such a scenario, i.e. even if Jira is accessed on URL4 - such issues as gadgets not displaying properly shouldn't be happening