Pester Tests for Web API cmdlets

[hjorslev]

Describe "Functionality"

Add Pester tests for

• Get-SteamFriendList Rework Get-SteamFriendList #75
• Get-SteamNews Rework Get-SteamNews #77
• Get-SteamPlayerBan Rework Get-SteamPlayerBan #78
• Get-SteamPlayerSummary Rework Get-SteamPlayerSummary #80
• Resolve-VanityURL Rework Resolve-VanityURL #71

Context "Private or Public? What are the use cases? Parameters? Options?"

Context "Additional Information"