[CLI] Set debug constants during boot

[bgrgicak]

This PR sets the WordPress debug constants during the CLI boot.

Depending on the --debug flag, WP_DEBUG, and WP_DEBUG_LOG will be set to true or false during boot. The WP_DEBUG_DISPLAY constant will always be set to false to match the Website behavior.

Disabling WP_DEBUG_DISPLAY will also avoid crashing the CLI during boot if a plugin activation fails. Long-term https://github.com/WordPress/wordpress-playground/issues/1979 shouldn't crash Playground anymore, but we still want these constant defaults in the CLI.

Testing Instructions (or ideally a Blueprint)

• Store this blueprint on your machine

  {
  "steps": [
  {
    "step": "installPlugin",
    "pluginData": {
      "resource": "wordpress.org/plugins",
      "slug": "002-ps-custom-post-type"
    },
    "options": {
      "activate": true
    }
  }
  ]
  }

• Start the CLI with the blueprint (change the BLUEPRINT_PATH to match your path)

  bun ./packages/playground/cli/src/cli.ts server --debug --blueprint BLUEPRINT_PATH

[adamziel]

I like having a --debug option, thank you @bgrgicak. I have concerns about the details and I left some comments.