Drop deprecated netstandard

[AlexNDRmac]

By creating this pull request, I confirm the following:

• I have read the CONTRIBUTING document.
• My change requires a change to the documentation.
• I have added tests to cover my changes.
• I have updated the documentation accordingly.
• I updated the CHANGELOG.

Types of changes:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Link to issue (if exists):

Small description of changes:

• Upgraded .NET Core runtime to .NET 7.0 for Tests and Examples projects
• Drop support for .NET Core 2.1 and 3.1 (dropper netstandard 1.x)
• Updated netstandard min version to 2.0
• Removed InheritDoc tool from the project
• Upgraded NET Framework min supported version to 4.6.2

Thanks