NBdev Jupyter Lab Extension

This is a feature idea/request.

**What**: Jupyter Lab NBDev extension

**Functionality**: Ability to do run common NBDEV functionality within Jupyter Lab without needing terminal. Having a menu on the left side where the file browser, and other extensions create their own panes would be great. Examples of functions include creating a new git repo project, Adding git hooks, Building Docs, building the library, cleaning notebooks, etc.

**Other Thoughts**: If it was designed with the git extension taken into consideration that would be great, since that already has notebook diffs which could be a good synergy.

The payload names no files or tests; begin by surveying nbdev's existing commands and JupyterLab extension integration points. Define the initial scope from the listed workflows and assess how the JupyterLab git extension would interact with them. Done should mean an agreed design and working coverage for the selected operations.

Written by the indexing model from the issue text.