Notebook support (fixes #71)

[bigbug]

Work in progress for creating notebook renderer support.

The extension shall listen for the following mime types:

• application/json
• application/json+graphviz-interactive-preview
• text/plain
• text/x-json
• text/x-graphviz
• text/x-dot

[bigbug]

Toolbar has been recreated with react for the notebook view:

[bigbug]

Rendering within a notebook:

[bigbug]

File saving and communication with main extension (needed especially for file saving) now works.

[bigbug]

Problem: Zoom on Image -> Change render engine -> zoom again There is a blip the zoom

[bigbug]

DataSelector is implemented:

[bigbug]

Search does not work properly at the moment

[bigbug]

Release is blocked due to bug in VSCode https://github.com/microsoft/vscode-webview-ui-toolkit/issues/377

[bigbug]

Notebook communication with extension host established. Configuration gets passed down to the notebook renderer. The renderer now has to consume it properly.

[tintinweb]

The edge tracing seems to be off when searching for nodes/edges:

this version (a and b2 should not be highlighted).

appears to be correct in the currently released version:

[bigbug]

@tintinweb : Search has been fixed