feat(store): add object-style StoreModule.forFeature overload w/fixes

[brandonroberts]

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
[ ] 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?

Builds on top of the original PR by @lacolaco to add interop with Redux Toolkit style of { name, reducer }, with additional fixes for AOT compliance. Also added usage to the example app. In order to preserve original commit author, the PR will be rebased and merged if it lands.

Closes #2809

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[timdeschryver]

Nice!