Defactor: remove TypeScript, native classes / decorators, ember-concurrency

[buschtoens]

This PR removes all non-essential niceties to reduce bundle size for users that don't use ember-concurrency and ember-decorators. It also reverts TypeScript back to the oldschool Ember Object Model to enable merging with ember-engines / ember-asset-loader / Ember core.

Fixes #3. Most likely also fixes #2.

/cc @villander @dgeb

[villander]

@buschtoens I don't understand this line, because it's always will be equal

{} !=== {}

[buschtoens]

Talked about this on Discord, but for anyone following along at home and also wondering:

Previously loadEngine was a restartable ember-concurrency task, meaning that whenever a new instance is started, any old potentially still running instance is cancelled. This is to make sure that, we don't accidentally render stale content, because of async calls, when the input arguments change.

The trick here with {} is:

{} === {} // => false

const obj = {};
obj === obj // => true

Whenever loadEngine is called it starts a new "thread", which then sets this._threadId to a new object. So any old still running threads would then compare there own closure threadId to the new this._threadId, which is then unequal.

[villander]

sound good, thank you bud