Build an enhanced query editor

[Bargs]

Part of #10789

The current query bar is a simple text input. It doesn't help the user build a query in any way. Now that we've developed a custom query language that Kibana can parse and understand we can build a more powerful editor. This is a meta ticket that will serve as a wish list of features we'd like to see in an enhanced query editor. We'll want to keep these things in mind as we think about a technical implementation so we don't paint ourselves into a corner.

• Syntax highlighting Query input bar should highlight syntax errors #70724
• Error detection and highlighting (annotations?)
• Autocomplete
• Multi-line support
• Auto-formatting
• ???

Child issues:

• Autocomplete

[elasticmachine]

Pinging @elastic/kibana-app-arch (Team:AppArch)