WIP: Populate companyname and other properties for PSResourceInfo

[anamnavi]

When installing a package, save companyname, copyright and other metadata information to metadata xml file. Also change setters access levels for these properties of the PSResourceInfo class. Get-PSResource will now return consistent information for packages installed with Install-PSResource cmdlet after this fix.

When finding a package, companyname and other related information is not easily accessibly via the json metadata (IPackageSearchMetadata object returned via NuGet GetSearchAsync() and GetMetadataAsync() search APIs and currently is more operational cost than is worth to get this field. Here is a link listing the package information accessible via the package nuspec (note company name is not listed): https://docs.microsoft.com/en-us/nuget/reference/nuspec

PR Summary

PR Context

Resolves #267

PR Checklist

• [x] PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• [x] Summarized changes
• [x] Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• [ ] This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: or [ WIP ] to the beginning of the title (the WIP bot will keep its status check at Pending while the prefix is present) and remove the prefix when the PR is ready.
• Breaking changes
  • [x] None
  • OR
  • [ ] Documentation needed
    • [ ] Issue filed:
• User-facing changes
  • [x] Not Applicable
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  • [ ] Documentation needed
    • [ ] Issue filed:
• Testing - New and feature
  • [ ] N/A or can only be tested interactively
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  • [x] Make sure you've added a new test if existing tests do not effectively test the code changed
• Tooling
  • [x] I have considered the user experience from a tooling perspective and don't believe tooling will be impacted.
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  • [ ] I have considered the user experience from a tooling perspective and enumerated concerns in the summary.

[PaulHigin]

@anamnavi, @alerickson please look at authenticode check test failures.