[Moving] Move Observability Onboarding folder into /x-pack/observability_solution#177458

CoenWarmer merged 10 commits intoelastic:mainelastic/kibana:mainfrom

CoenWarmer:feat/move-obs-plugins-observability-onboardingCoenWarmer/kibana:feat/move-obs-plugins-observability-onboardingCopy head branch name to clipboard