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
This change fixes 3 issues:
- According to [PowerShell Language Specification Version 3.0](https://www.microsoft.com/en-us/download/details.aspx?id=36389), as quoted: "_The result is the (possibly empty) unconstrained 1-dimensional array_", `@(...)` should only return `object[]` array.
- `@([object[]]$null).GetType()` fails with error `"You cannot call a method on a null-valued expression."`
- `@([System.Collections.Generic.List[object]]$null)` fails with error `"Object reference not set to an instance of an object."`