Deprecate authToken

[marcsanmi]

Problem

When using the authToken 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 authToken for authentication in Grafana Cloud.

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