[GraphManager]  update saveing active graph to DB

DONE:
- update saveActiveGraphToDB() in GraphManager, add functionality from
  saveGraphToDB slot in CoreWindow, so this slot now only call this
  method. This change was needed because coreWindow shoud not test
  connection and know how saving is proceed.

TODO:
- separate saveLayout from CoreWindow to GraphManager
- in saveLayout when is not saved yet, add saveing it instead of canceling method
- in saveing graph or layout add other test than conn.open that cause delay and freeze
[GraphManager] add saveActiveLayoutToDB() method

DONE:
- move functionality for saveing layout from CoreWindow to new added
  saveActiveGraphLayoutToDB() method in GraphManager. In CoreGraph is only
  getting name for layout via InputDialog and saveing functionality is in
  GraphManager. In next step will be easier to save graph before saving
  layout if needed.

TODO:
- in saveLayout when is not saved yet, add saveing it instead of canceling method
- in saveing graph or layout add other test than conn.open that cause delay and freeze
[GraphManager] add saving Graph to saving Layout first if needed

DONE:
- update saveActiveLayoutToDB() method, add saving Graph if it is not
 saved before saving layout.

TODO:
- in saveing graph or layout add other test than conn.open that cause delay and freeze