Add warning message if code page is not UTF-8

[FabienTschanz]

Pull Request (PR) description

This PR adds a warning message if the current ANSI code page is not set to UTF-8, but rather e.g. Windows-1252, which is the default for Windows PowerShell 5.1.

Windows PowerShell uses the old-fashioned Windows-1252 code page, which is not compatible with UTF-8 characters outside of the ASCII character range (7-bit). This means that special characters, very common in Europe, will lead to parsing errors during report generation or compilation of the configuration. This is because those Unicode characters are not properly displayed in the Windows-1252 code page.

PowerShell 7 doesn't suffer from this problem because it's default code page is already set to UTF-8.

@ykuijs Waiting for your confirmation that this solves the encoding issues of your customer.

This Pull Request (PR) fixes the following issues

• Fixes New-M365DSCReportFromConfiguration: en dash in EXOGroupSettings DisplayName causes DSCParser exception #5202
• Fixes AADUser: encoding issue #5669
• Fixes [SCSensitivityLabel] How to handle Unicode characters in Comments property (and a few others) #4824

Task list

• Added an entry to the change log under the Unreleased section of the file CHANGELOG.md.
  Entry should say what was changed and how that affects users (if applicable), and
  reference the issue being resolved (if applicable).
• Resource parameter descriptions added/updated in the schema.mof.
• Resource documentation added/updated in README.md.
• Resource settings.json file contains all required permissions.
• Examples appropriately added/updated.
• Unit tests added/updated.
• New/changed code adheres to DSC Community Style Guidelines.