Moved CSV from mount to copy

[MatthewJSalerno]

Since we are already creating an overlay image, we might as well move it here. In one of my builds it was build mounted as a directory. Probably just my docker syntax, but completely avoidable if we copy it from here.

[derekslenk]

Just an FYI, it can be mounted as a file, but it has to be the full path to the file and in quotes, eg:
"/home/drone/docker-scripts/service-names-port-numbers.csv:/etc/graylog/server/service-names-port-numbers.csv:ro"

You of course can have a variable in there:
"${DOCKER_HOME}/service-names-port-numbers.csv:/etc/graylog/server/service-names-port-numbers.csv:ro"

To get this to work you will have to remove the directory the old script created first.