Removed unused schemas and updated the remaining for Spring 4.1.

At least caching of learning progress responses
did not work since commit a59eb75f on March, 6th.

While the exact origin of this problem is unclear,
it seemed like Spring was creating more than one
databaseDao bean. One of these beans had no
working caching annotations.

This will allow dynamic configuration depending on property file settings.

Removed connector client bean from XML based configuration and added bean
creation into JavaBased config class. Bean will be created if there is
a property "connector.enable" with value "true" otherwise no bean will
be created wich has the same behavior removing bean definition from XML
configuration file.

No need to change application config - can be done in property file :-)

Permission handling is the same as with removed Authorized annotation

Connector bean has to be disabled because connector could not get any
connection to database server. Connection to database server is
forbidden.

This sets current user and ARSnova session information in a session
scoped service bean. If the user connects with a websocket, the
websocket session ID will be set in addition to the user and session
object.

The aspects methods pointcut after returning from joinSession() method
in SessionService. So the UserSessionService will be set with all needed
data after a user successfully joins a session.

With this service available, it can be used to replace some usage of
Array/Map based application wide data structures that cause some trouble
when stopping or redeploying the application.

Use service and dao beans in application context and controllers in
servlet context. This prevents controller beans from being created twice
in application and servlet context witch causes some trouble in the
past.