Continued with DHT stuff:

Continued with DHT stuff:
- added a very generic way to query the local DHT for key/value matches
- used this way to look for DHT nodes accepting bootstrap requests.
- renamed method DhtObjectFactory::createDhtObjectInstance to createDhtInstance
  to match with its getter/setter mates.

Signed-off-by: Roland Haeder <roland@mxchange.org>