Selection/highlight write API docs

[lmeyerov]

• [ ] doc str
• [ ] storybook: react
• [ ] storybook: vanillajs

Need at least a minimal demo to share w/ Gadi, and we can pause on exposing these until ID-based version is ready

[lmeyerov]

Closing as duplicate of https://github.com/graphistry/graphistry-js/issues/112