Proposal for implementing OpenTelemetry plugin for introducing
observability feature in Tacker. OpenTelemetry is the one of the most
popular framework for providing observability and covering comperensive
usecases not only for VNF/CNF but also infra features [1].
[1] https://opentelemetry.io/
Implements: blueprint otel-monitoring
Change-Id: If35a064a966bdd5e59dab66367ca3218e7c12637
Signed-off-by: Yasufumi Ogawa <yasufum.o@gmail.com>