allow disabling auth check

[vindex10]

For a small but important scope of tasks Admin role is not required. For example dumping the dashboards, which is where all the knowledge is stored. I suggest the following flag to be able to disable admin check if needed.

use env var API_AUTH_CHECK=false or a corresponding config field api_auth_check: false

[acjohnson]

Thank you for this @vindex10 😄