Added 2nd Calculator Sample to Support Localization

[arpavan]

Description

This PR adds a second Calculator sample solution to support the already available second test plan testPlanWithCommaForDecimal.fx.yaml for executing this test in regions that use numbers for commas for decimals. The test plan sample was already available but did not provide with it the sample app for users to run against. This PR covers that gap.

This one also includes a README explaining the two variations and pointing users to the correct sample app to use for each sample.

Checklist

• [N/A] The code change is covered by unit tests. I have added tests that prove my fix is effective or that my feature works
• [N/A] I have performed end-to-end test locally.
• [N/A] New and existing unit tests pass locally with my changes
• [N/A] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [N/A] My changes generate no new warnings
• [x] I used clear names for everything
• [x] I have performed a self-review of my own code

[github-actions[bot]]

Package	Line Rate	Branch Rate	Complexity	Health
Microsoft.PowerApps.TestEngine	91%	88%	925	✔
Summary	91% (2457 / 2686)	88% (559 / 636)	925	✔

Minimum allowed line rate is 85%