Agree on conventions across components

[romaricpascal]

What

Establish conventions shared by our different components' JavaScript API, both from the perspective of:

• architecture (eg. events or callbacks? composition or inheritance? getter/setter properties or get.../set... methods?...)
• naming (eg. leading $ for elements, name of the property storing the component's root element...)

Why

This will help us provide developers a consistent experience across our components, as well as guide us in the implementation of the API of the different componens

Who needs to work on this

Developers

Who needs to review this

Developers

Done when

• [ ] We have a document listing the conventions we've chosen and why we chose them
• [ ] We have trialed (on paper) the conventions on different components to verify they'd work OK with our current set of components

[romaricpascal]

Starting to discuss in this document (internal).