Theming: best practices

[vodolazkayamv]

Platform

• iOS
• macOS

Describe the feature that you would like added

Right now documentation lacks information on how to customize components in a way they were designed to be customized.
It would be great to have an overview of theming capabilities (setting primary app colors, etc.) and best practices (and things to avoid) for every component which has some specific ways to be customized.

What component or utility would this be added to

Documentation.

Have you discussed this feature with our team, and if so, who

See #61 (comment)

[markavitale]

@harrieshin we should consider whether this best lands in the repo here or on the fluent ui control documentation site: https://developer.microsoft.com/en-us/fluentui#/controls/ios. Note that the Fluent UI web equivalent seems to be documented on the Fluent UI controls documentation website: https://developer.microsoft.com/en-us/fluentui#/controls/web/references/isemanticcolors

[markavitale]

In general though, we haven't put a ton of technical documentation on that site, so maybe having something internal to the repository makes more sense.