fix: [WIN-NPM] back-compat mitigation to PATH issue

[huntergregory]

Reason for Change:
Resolve PATH issue correctly. Removing powershell.exe is back-compat with NPM v1.3.34 (in-prod).

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests

Notes:
Don't want to override PATH variable.

Error

powershell.exe : The term 'powershell.exe' is not recognized as the name of a cmdlet, function, script file, or
operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try
again.
At line:1 char:27
+ .\setkubeconfigpath.ps1 ; powershell.exe .\npm.exe start --kubeconfig ...
+                           ~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (powershell.exe:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

[vakalapa]

@rbtr @matmerr wdyt ?

[vakalapa]

I am not sure if overriding the PATH value here is the right choice, we should append this new PATH to the existing PATH. guess doing it in Dockerfiles is the right way ? or taking in this variable as NEWPATH and appending this NEWPATH to PATH in the Dockerfiles

[huntergregory]

appending now, although there might be a better fix that doesn't modify PATH. Looks like there was a regression in the NPM build some time after 02/06

[huntergregory]

appending with %PATH% doesn't actually append anything

[huntergregory]

remove our first attempt at mitigation, which is not back-compat and is incomplete (can't use vfpctrl and other tools used by HNS to collect logs)