Deprecate auth_token

[marcsanmi]

Problem

When using the auth_token for Grafana Cloud, users encounter a confusing error message:

[ERROR] upload profile: failed to upload. server responded with statusCode: '401' and body: '{"status":"error","error":"authentication error: legacy auth cannot be upgraded because the host is not found"}'

Solution

We should deprecate the use of auth_token for authentication in Grafana Cloud

Warn users if auth_token is specified and the URL is not pointing to the OG Pyroscope Cloud.