InjectionToken<...> for public providers in piral-ng

[hwanders]

New Feature Proposal

Add typed InjectionToken<...> constants to piral-ng and use them when providing piral, Props and Context using those tokens in the dependency injection container.

Description

For downward-compatibility the string-based providers should probably be kept.
The relevant source code parts are:

• module.ts:

  piral/src/converters/piral-ng/src/module.ts

  Line 40 in 1c113ff

  const providers = [

• standalone.ts:

  piral/src/converters/piral-ng/src/standalone.ts

  Line 49 in 1c113ff

  app = createApplication({

Background

Some application developers prefer the new inject(...) funtion over the classic @Inject(...) annotation.
inject is typed more strictly, it does not allow a simple string parameter anymore, like @Inject.
So writing inject('piral') will fail in a type checking error.

Since the token passed to inject must exactly match the one used as provide key, developers currently can not use the the inject function without using type-avoiding hacks (like inject('piral' as any)).

Example

The following is an ad-hoc change, without even compiling/building Piral.
hwanders@84347a9

[FlorianRappl]

Sounds great - want to make a PR?