Add option to display service metadata

[johnstairs]

tyger login status --format json

will display connection and service metadata in JSON format:

{
  "serverUri": "https://abc-tyger.westus2.cloudapp.azure.com",
  "principal": "api://tyger-test-client",
  "metadata": {
    "authority": "https://login.microsoftonline.com/76d3279b-830e-4bea-baf8-12863cdeba4c",
    "audience": "api://tyger-server",
    "cliAppUri": "api://tyger-cli",
    "capabilities": [
      "NodePools",
      "DistributedRuns"
    ]
  }
}