Split up security.py into chunks for each application.

The file lib/canonical/launchpad/security.py contains authorization adapters for all parts of Launchpad. It is loaded by this directive in lib/canonical/launchpad/configure.zcml that registers all IAuthorization adapters found in it:

<authorizations module="canonical.launchpad.security" />

Looking at the implementation of the "authorizations" directive in canonical.launchpad.webapp.metazcml.authorizations, there is no reason it could not be called multiple times, like so:

<authorizations module="lp.answers.security" />
<authorizations module="lp.bugs.security" />
<authorizations module="lp.code.security" />
etc.

This would make each chunk much smaller and more managable. AuthorizationBase could remain in its current place to be included by the other security modules.

This is a first simple step towards a simpler security system.