Fix 4 P1 bugs for Sprint42

1761320 [PowerShell] Parameter -Environment enum values are not well documented
1975232 [Powershell] cmdlets help content bugs
2470941 [PowerShell] get-help <cmdlet> -online will throw error. expect it to redirect users to online page
1720534 [PowerShell for XSMB] enable accepting objects from pipeline to enable multi-task in File cmdlets