feat(signals): add resource extensions

[markostanimirovic]

PR Checklist

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

Closes #5126

Does this PR introduce a breaking change?

[ ] Yes
[x] No

[michael-small]

IMO each of the built in extensions could use their respective import in each block. Not all imports in a block, but definitely 1:1 with each of the 4 functions.