Interactive `/container` install script

[mobileskyfi]

Tried a few different approach to how to script install on RouterOS. In newer RouterOS there is the /console/ask so instead of static example script, it prompt for the disk to use, confirm /container/env to use, etc.

[mobileskyfi]

i.e. The current example script just copies the README.md instructions, and put them in one file, see here:
https://github.com/tikoci/netinstall/blob/master/examples/scripts/setup-netinstall.rsc