Remove copied Vitess docker scripts

Currently, we're using vitess/lite as the base image and build our own vitess docker image. vitess/lite misses some important components such as etcd, vtctl, and mysqlctl binaries.

Once Vitess provides an all-in-one docker image with reasonable size (<= 1G), we can remove the following Vitess docker scripts that are copied from the Vitess repository .

• src/docker/local/scripts/vttablet-up.sh
• src/docker/local/scripts/vtgate-up.sh
• src/docker/local/scripts/vtctld-up.sh
• src/docker/local/scripts/mysqlctl-up.sh
• src/docker/local/scripts/etcd-up.sh
• src/docker/local/env.sh
• src/docker/local/initial_cluster.sh
• src/docker/install_local_dependencies.sh