feat: add support for running on AWS Lambda managed instance types

[herin049]

Adds support for running on AWS Lambda managed instances.

Lambda managed instances differ from standard lambda functions in several areas, but the differences most relevant for the OpenTelemetry collector layer are:

• For Managed instance types the Extension API does not allow subscribing to the Invoke event type.
• For Managed instances the telemetry API does not report platform.runtimeDone events
• A Managed Lambda instance is never frozen (removes the need for the decouple processor)
• Multiple Lambda processes can be created within a single execution environment (this is particularly relevant for ensuring that auto-instrumentation works with the bootstrap script)
• Multiple Lambda function invocations may be simultaneously in process for a given execution environment

For more information see: https://docs.aws.amazon.com/lambda/latest/dg/lambda-managed-instances.html

In order to accommodate the changes above, the following changes have been made to the layer if the extension determines the initialization type is lambda-managed-instances using the AWS_LAMBDA_INITIALIZATION_TYPE environment variable:

• The Extension no longer subscribes to the Invoke event type, and the extension no longer subscribes to the telemetry API to listen for the platform.runtimeDone event if the initialization type is lambda-managed-instances
• The decouple processor is no longer added to any pipelines.
• The FunctionInvoked() and FunctionFinished() lifecycle methods are no longer invoked for lifecycle listeners.
• The wrapper script has been updated to instrument inside the wrapper script itself to ensure instrumentation is properly applied for newly created Python processes. (applies to all initialization types)
• A few changes have been made to the telemetry API receiver to accomidate changes to the events reported by the telemetry API.

I have added relevant unit tests and have manually verified the implementation using the following repo: https://github.com/herin049/aws-lambda-managed which configures the layer to export signals to Grafana cloud.

[serkan-ozal]

Hi @herin049,

For the Python SDK related changes, as far as I understood from your explanations, AWS_LAMBDA_EXEC_WRAPPER is not taken care for the spawned Lambda processes (but main Lambda runtime process) in Lambda managed instances. Is that correct? Is there any official AWS documentation mentioning/explaining this behavior?

Because otherwise (if AWS_LAMBDA_EXEC_WRAPPER could still be used for the spawned Lambda processes) opentelemetry-instrument CLI would instrument spawned Lambda processes.