LESS cache is not re-used if the request comes from a different host

Use-case:

• Browse the wiki locally, using http://localhost:8080 as host
• Then browse the same wiki, but with a different url, like http://www.xwiki.org or http://my-public-url/xwiki.

The cache is not re-used because the host (localhost or my-public-url) is part of the cache key.

This has been done for the purpose of XWIKI-11731. We needed to put the URL in the cache key. But actually, only the "path" part of the URL is needed. We don't need to store http//localhost:8080/xwiki/myResource, but only /xwiki/myResource.

This is the fix I'm going to commit.