Force users to respect the DB limit when renaming/moving/copying a page

When performing some refactoring operation on a page or a set of pages, the DB limit for name size can currently be reached. This could led to errors on all pages, or on some pages creating inconsistencies in the wiki.

To avoid this, we should prevent users for doing such operations by checking the size of new pages names against the DB limit before performing the operations.
On UI side this should block the current operation, as long as the limit is reached.
On REST/scripting side, this should trigger an understandable exception.