Added All Required Coop.Core.Common Namespace Comments

[garrettluskey]

PR Checklist

Please check if your PR fulfills the following requirements:

• All new classes have class-level documentation comments, if there are any at all
  N/A Tests for the changes have been added (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• 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 not work as expected)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation update
• Other... Please describe:

What is the current behaviour?

Some classes in the Coop.Core.Common namespace were missing summary xml comments.

What is the new behaviour?

Resolves #643

Adds summary xml comments to all classes in the Coop.Core.Common namespace

Other information