Add Teams Admin Function

[weyCC81]

Add the following functions:

#Get-AccessTokenForTeamsAdmin # Sign-In to Teams Admin Center (TAC)
Get-AADIntAccessTokenForTeamsAdmin -SaveToCache

Run some requests:

Get-CsTenant
Get-CsTenantFederationConfiguration
Get-CsTeamsExternalAccessConfiguration
#Get-TeamsExternalChatConfiguration # Summary
Get-AADIntTeamsExternalChatConfiguration

Reference: https://www.alweys.ch/