Add more tips and tricks

[jakeboone02]

• Using an array-based value editor with multiple inputs for "between" or "in" operators
  • Date/number range picker (Add docs for option group support #5)
• Validation tips
• Async value editor with react-select
• Option groups in a custom ValueSelector
• Compare fields to other fields (do we need an official way to do this?)
  • Codesandbox demo
  • RQB issue #192
• Relative dates ("today + 7", etc.)
• transformQuery usage and examples