[vscode-diagrams] Explicit synchronization between diagram and texteditor

The hightlighting of the selected Element in the texteditor is now explicit.

Changed the key- and mousebindings for mutliple features:

• Open Actor Substructure in Diagram: double click
• Open and highlight selected eTrice Element in Texteditor: ctrl+shift+alt+m
• Open structure Diagram from inside behavior diagram: ctrl+shift+alt+s
• Open behavior Diagram from inside structure diagram: ctrl+shift+alt+b