Update links that contain 'en-us' culture to remove 'en-us' culture (if possible) and in some cases update to newer re-directed link to docs.microsoft.com
* add insider release notes
* note that issue should be fixed in beta 4
* fix spelling error in no known workaround
* fix spelling of pre-release
* Add new words to spelling dictionary for NanoServer-insider release
* fix spelling of PackageManagement
This change is made at the request of the PowerShell committee,
as the use of "stable" implied more stability than available with alpha
releases. This also changes the images from existing under one repo to
two: powershell/powershell and powershell/powershell-nightly.
The documentation and script have been updated.