destroy script is removing all networks on host, not just local to project

[njappboy]

docker-mysql-proxysql/docker-compose-destroy.bash

Line 13 in fe8c6be

docker network prune -f

^ This removes all networks on host, unlike the docker volumes prune command which just removes local volumes.

Suggest:

docker network rm docker-mysql-proxysql_frontend
docker network rm docker-mysql-proxysql_backend