Description:
This PR introduces CodeMirror6 when creating GraphQL API keys. This is to lay the groundwork for:

• markdown /w preview
• Better experience for Expr fields
• versioned API keys /w diff output

Out of Scope:

• markdown and expr modes/editors will be done separately

Screenshots:

Describe any introduced user-facing changes:
Creating GraphQL API keys is now done in an editor rather than a text field

• dialog is wider
• syntax highlighting
• format option
• auto-complete

Describe any introduced API changes:
N/A