WIP: Allow for persistence in Cytoscape component.

[ManInFez]

About

This PR is about solving the issue of persisting component information natively.
resolves #113

Description of changes

• Added new demo for usage of persistence.

Pre-Merge checklist

• The project was correctly built with npm run build:all.
• If there was any conflict, it was solved correctly.
• All changes were documented in CHANGELOG.md.
• All tests on CircleCI have passed.
• All Percy visual changes have been approved.
• Two people have 💃'd the pull request. You can be one of these people if you are a Dash Cytoscape core contributor.

Reference Issues

closes #113

Other comments

Currently very much a WIP

[xhluca]

@ManInFez I haven't forgotten about this PR! There's a few things I wanted to get done (update react/react-dom to 16, update docgen, and actually add persistence) before reviewing this. I'll ping you again when I'm ready to review this.

[xhluca]

I'll review this once #125 is merged