Is your feature request related to a problem?
No

Describe the solution you'd like
From the specification on general SDK configuration: OTEL_SDK_DISABLED should, if set to true, disable the SDK for all signals.

Describe alternatives you've considered
N/A

Additional context
The configuration as an environment variable should appear here: https://github.com/open-telemetry/opentelemetry-python/blob/main/opentelemetry-sdk/src/opentelemetry/sdk/environment_variables.py.