[META] Prepare Grok Debugger for new platform

[jen-huang]

This ticket outlines the necessary work to migrate Grok Debugger to the new platform.

Potential blockers

• A few ace editor dependencies
• DevToolsRegistryProvider dependency

Steps necessary for migration

Client Side

• Convert all code to Typescript
• Remove all Angular UI - most of Grok Debugger is already in React (done in EUIFication: Grok Debugger #20027), but there are still some bootstrapping Angular directives, modules, and factories
• Migrate from the Angular Router to React Router: relevant LOC
• Create the legacy shim for your NP-style plugin shape
• Move all imports from ui/* to your frontend Legacy shim
• More steps here: https://github.com/elastic/kibana/blob/master/src/core/MIGRATION.md#browser-side-plan-of-action

Server Side

• Move all server.plugins.* calls to your backend Legacy shim
• More steps here: https://github.com/elastic/kibana/blob/master/src/core/MIGRATION.md#server-side-plan-of-action

[jen-huang]

Closing as Grok Debugger has been migrated.