Allow creators to add/set custom classes or tags to components

**Describe the feature request**
Currently, for styling Budibase apps, creators have the option to provide custom CSS rules in most components.

If a creator wanted to, they could provide a complete style sheet in an `embed` component, but finding and setting selectors is very difficult.

This feature request asks for the ability to add CSS classes to components which could then be picked up by CSS selectors in an embed component. The request comes from a customer who wants to use it in conjunction with `driver.js` - https://driverjs.com/

Start by locating the component implementations and the existing custom CSS controls, then inspect how the embed component applies CSS. Determine the scope of components that should accept custom classes or tags and verify that creators can use those selectors with driver.js and embedded CSS.

Written by the indexing model from the issue text.