Add Interactive2DPlot

Summary of Changes

If one wants to compose a visualization with Vega, then all of the interaction state from Vega is currently inaccessible via Python due to it only being available in Vega signals. This adds a wrapper around vega.Figure that binds listeners to Vega signals and syncs their state values with the Trame state.

Checklist

• The MR has a clear and concise title
• Code is self-documented and follows style guidelines.
• Automated tests are written and pass successfully.
• Regression tests (e.g. manually triggered system tests, manual GUI/tool tests, ...) are performed to make sure the MR does not break anything (when applicable)
• Readme file is present and up-to-date.

Documentation Updates

Additional Notes

I tested this briefly with the SANS GUI and this component allows us to remove the custom JS script prepare_charts.js.

Closes #15 (closed)