LP #143604: Removed top-level database-quota-size from zope.conf, some storages support a quota option instead.

LP #143089: Removed the top-level zeo-client-name option from zope.conf, as it had no effect since ZODB 3.2.

Applied patch from https://bugs.launchpad.net/zope2/+bug/257675, avoiding the mysterious '-C' in request.form

Moved the code handling ZCML loading into the ``Zope2.App`` package. The component architecture is now setup before the application object is created or any database connections are opened. So far the CA was setup somewhat randomly in the startup process, when the ``Five`` product was initialized.

Downgrade the ``manage_* is discouraged. You should use event subscribers instead`` warnings to debug level logging. This particular warning hasn't motivated anyone to actually change any code.

Integrated the Products.signalstack / z3c.deadlockdebugger packages. You can now send a SIGUSR1 signal to a Zope process and get a stack trace of all threads printed out on the console. This works even if all threads are stuck.