Added plugin support

[thehenrytsai]

• Added plugin support for MessageStore, DataStore, ResumableDataStore, EventLog and EventStream.
• Exposed config for EventStream.
• Exposed config for ResumableTaskStore.
• Refactored/consolidated repeated test code.
• Various renames.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 96.80000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 95.65%. Comparing base (24199fa) to head (d12c607).

Files	Patch %	Lines
src/storage.ts	96.51%	3 Missing :warning:
src/index.ts	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #145 +/- ## ========================================== + Coverage 95.64% 95.65% +0.01% ========================================== Files 27 28 +1 Lines 2869 2922 +53 Branches 374 393 +19 ========================================== + Hits 2744 2795 +51 - Misses 124 126 +2 Partials 1 1 ```

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