feat(store): add USER_RUNTIME_CHECKS public token

[timdeschryver]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/ngrx/platform/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Documentation has been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Only way to provide runtime checks is via store.forRoot()

Closes #1973

What is the new behavior?

Make it possible to define runtime checks via an injection token:

providers: [
  {
    provide: USER_RUNTIME_CHECKS,
    useValue: {
      strictStateImmutability: true,
      strictActionImmutability: true,
      strictStateSerializability: true,
      strictActionSerializability: true,
    },
  },
],

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information