feat(datastore): Make thread pool size configurable

[jvh-aws]

• PR title and description conform to Pull Request guidelines.

Issue #, if available: #3152

Description of changes: Allow a configurable thread pool size for DataStore

How did you test these changes?
Unit tests and manually verifying that the correct thread pool size is used

Documentation update required?

• No
• Yes (Please include a PR link for the documentation update)

General Checklist

• Added Unit Tests
• Added Integration Tests
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Ensure commit message has the appropriate scope (e.g fix(storage): message, feat(auth): message, chore(all): message)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

❌ Patch coverage is 70.58824% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 54.79%. Comparing base (7a084cd) to head (7f446ec).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3170   +/-   ##
=======================================
  Coverage   54.78%   54.79%           
=======================================
  Files        1048     1048           
  Lines       31329    31343   +14     
  Branches     4690     4693    +3     
=======================================
+ Hits        17165    17175   +10     
- Misses      12356    12360    +4     
  Partials     1808     1808           

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