Ability for plugins to override existing xwork actions

There is no clean way of overriding existing xwork actions through the plugin infrastructure.

The recommended solution (discussed in this thread) is reproducing the pages package in the atlassian-plugin.xml, or making the change directly in xwork.xml.

The solutions is not appropriate for plugins because:

• copy-pasting the pages packages from xwork.xml would require having a version of the plugin for each version of confluence that has changes on xwork.xml
• Replacing the class in xwork.xml would not work either, because it is read upon startup, before the plugins are loaded, thus the loader does not find the new class (lots of exceptions thrown)