Introduce a meter provider to the buildx cli that will send metrics to
the otel-collector included in docker desktop if enabled.
This will send usage metrics to the desktop application but also send
metrics to a user-provided otlp receiver endpoint through the standard
environment variables.
This introduces a single metric which is the cli count for build and
bake along with the command name and a few additional attributes.
Signed-off-by: Jonathan A. Sternberg <jonathan.sternberg@docker.com>
