Merge branch '628-update-istio-to-1-9' into 'master'

Update Istio to 1.9

Closes #628, platform-one/big-bang/apps/core/authservice#16, platform-one/big-bang/apps/core/istio-operator#13, and platform-one/big-bang/apps/core/istio-controlplane#34

See merge request platform-one/big-bang/bigbang!726