Based on standard practices, we need to have a copyright and license notice at the top of each source file. Removed existing copyrights and updated/added copyright notices for .h, .cpp, .cs, .ps1, and .psm1 files.
Updated module manifests for consistency to have Author = "PowerShell" and Company = "Microsoft Corporation". Removed multiple line breaks.
Separate PR coming to update contribution document for new source files: #6140
Manually reviewed each change.
Fix#6073
* Add autoload for TestHelpers.psm1
Test.Helpers.psm1 was renamed to TestHelpers.psm1
* Resolve conflit and rebase Add autoload for TestLanguage.psm1
* Remove unneeded comments from PSD1 files
* Rename test modules
Remove approved verbs (Get-Verb) from module names.
* Enhance ShouldBeErrorId to output exception into pipeline for later analysis
* Remove unneeded comments
* Resolve merge conflict
