Multi-tenant support for QS Cloud alerts

[mountaindude]

Background

Currently Butler only monitors a single QS Cloud tenant.

New feature suggestion

• Make it possible to monitor zero or more tenants, statically defined in the Butler config file
• Make it possible to monitor zero or more tenants, dynamically retrieved from a remote http endpoint that returns a JSON with information about the tenant, API key that should be used to connect to the QS Cloud API for a specific tenant, etc
  • The remote http endpoint should be secured (https + auth) somehow. Possibly using a JWT.