Opt in to Localization Validation - Fixes #206

[PlagueHO]

Pull Request (PR) description

• Removed suppression of PSUseShouldProcessForStateChangingFunctions PSSA rule because it is no longer required.
• Combined all StorageDsc.ResourceHelper module functions into StorageDsc.Common module and renamed to StorageDsc.CommonHelper module.
• Opted into Common Tests 'Common Tests - Validate Localization' - fixes Issue #206.
• Refactored tests for StorageDsc.Common to meet latest standards.
• Minor style corrections.
• Removed unused localization strings from resources.

This Pull Request (PR) fixes the following issues

• Fixes #206

Task list

• [x] Added an entry under the Unreleased section of the change log in the CHANGELOG.md. Entry should say what was changed, and how that affects users (if applicable).
• [ ] Resource documentation added/updated in README.md in the resource folder.
• [ ] Resource parameter descriptions added/updated in schema.mof and comment-based help.
• [ ] Comment-based help added/updated.
• [x] Localization strings added/updated in all localization files as appropriate.
• [ ] Examples appropriately added/updated.
• [ ] Unit tests added/updated. See DSC Resource Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Resource Testing Guidelines.
• [x] New/changed code adheres to DSC Resource Style Guidelines and Best Practices.

@johlju - would you mind reviewing this one when you have time?

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This change is 

[codecov-io]

Codecov Report

Merging #208 into dev will increase coverage by 1%. The diff coverage is 96%.

@@        Coverage Diff         @@
##           dev   #208   +/-   ##
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+ Coverage   94%    95%   +1%     
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  Files        8      7    -1     
  Lines      890    958   +68     
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+ Hits       838    917   +79     
+ Misses      52     41   -11