Public API for 3rd party integration

At the moment `ember-inspector` has bunch of initialization magic (checking for some special props to exist). It would be great to have minimal public API to avoid hacking it around. It allow us to bring ember inspector to wider community.

I had few experiments for `minimal` script to `boot` ember inspector in custom environments:

* Vite & Ember (modules) environment without `amd`, works with this `compat` file: https://github.com/lifeart/demo-ember-vite/blob/master/src/config/inspector.ts
* Glimmer like runtime, with created from scratch `boot` logic: https://github.com/lifeart/glimmer-next/blob/master/src/utils/ember-inspector.ts

No call to action here, just leaving some documentation (code references) how to deal with ember-inspector in 3rd party environments.

Start by reading the referenced src/config/inspector.ts compatibility file and src/utils/ember-inspector.ts boot logic. Compare how each initializes ember-inspector outside the usual environment, then clarify the minimal public API and its supported environments with maintainers. Done would require an agreed API and corresponding implementation, which this issue does not yet specify.

Written by the indexing model from the issue text.