Remove character encoding configuration from Confluence

Confluence should:

1) Serve all pages as UTF-8
2) Require that the application server interpret URLs as being UTF-8 encoded

All modern browsers support this configuration, but we will have to test all our supported appservers to ensure that they can be configured to support (2). And we'll have to provide documentation on how to do this configuration on each appserver.

This will resolve a lot of character encoding issues that are caused by users moving away from UTF-8. It will also mean we can phase out the truly ugly and bug-prone URL-rewriting and double-encoding hacks that plague the codebase.