XmlInfoProvider: new abstract template class
XmlInfoProvider: new abstract template class

The XmlInfoProvider is a base for classes providing a kind of an Info
object parsed from XML sources.

To utilize XmlInfoProvider a SAXHandler si required. A SAXHandler is
a class that implements Poco::SAX::ContentHandler interface and is
iterable over all parsed Info instances.

Signed-off-by: Jan Viktorin <3eab6ac54c005c4408f608556a6663b7f2abede7@fit.vutbr.cz>

BeeeOn/server,BeeeOn/server,BeeeOn/server,BeeeOn/server