Manage non-public clouds

As an IT pro I want to manage Power Platform resources that are in Government, China, or other non-public clouds.

[x] Discuss whether this should be a provider configuration setting ~~or an attribute on a resource~~
[ ] Implemented for BAPI client
[ ] Implemented for PP API client
[x] Test tenants that are in other clouds
[x] Fixing #53 is a prerequisite since locations will be different for other clouds

Design

provider "powerplatform" {
  cloud = "gcc" # public (default) | gcc | gcchigh | dod | ex | rx | china
}

Cloud	BAPI	Power Apps API	Power Platform API	OAuth Authority
`public`	`api.bap.microsoft.com`	`api.powerapps.com`	`api.powerplatform.com`	`login.microsoftonline.com`
`gcc`	`gov.api.bap.microsoft.us`	`gov.api.powerapps.us`	`api.gov.powerplatform.microsoft.us`	`login.microsoftonline.com`
`gcchigh`	`high.api.bap.microsoft.us`	`high.api.powerapps.us`	`api.high.powerplatform.microsoft.us`	`login.microsoftonline.us`
`dod`	`api.bap.appsplatform.us`	`api.apps.appsplatform.us`	`api.appsplatform.us`	`login.microsoftonline.us`
`ex`	`api.bap.eaglex.ic.gov`	`api.powerapps.eaglex.ic.gov`	`api.powerplatform.eaglex.ic.gov`	`login.microsoftonline.eaglex.ic.gov`
`rx`	`api.bap.microsoft.scloud`	`api.powerapps.microsoft.scloud`	`api.powerplatform.microsoft.scloud`	`login.microsoftonline.microsoft.scloud`
`china`	`api.bap.partner.microsoftonline.cn`	`api.powerapps.cn`	`api.powerplatform.partner.microsoftonline.cn`	`login.chinacloudapi.cn`