Class names in namespaces should not be chosen as once we didn't have
such. The fact that we already did "use Db\Connection as DbConnection"
is the best hint that naming was wrong.
So this patch renames Db\Connection to Db\DbConnection and does the
same with DbQuery. DbQuery has been adjusted to fit our new SimpleQuery
and to handle the new Filter implementation.
When optional classes and php extensions like pgsql and additonal Zend-Pdos are
actually required by creating a new resource or authentication backend,
perform a check and display a warning instead of just throwing an exception.
refs #4788
Remove the old calls to DbAdapterFactory and use ResourceFactory instead. Remove
the DbAdapterFactory and fix all unit tests that have been broken due to the changes.
Change the functionality of the ResourceFactory to also handle LdapConnections
resolves#4587
