Introduce a `bin/test-scale` script to deploy Linkerd alongside sample
apps at scale.
This script deploys the following:
- Linkerd control-plane, with service profiles
- 5 namespaces x 5 replicas of each:
- Emojivoto demo app
- Books demo app, with service profiles
- Lifecycle / bb test environment
Fixes#2517
Signed-off-by: Andrew Seigner <siggy@buoyant.io>