Add option for using command and control instead of disk injects

[activeshadow]

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Originally created by @activeshadow on Thu, 21 Jan 2021 22:46:07 GMT

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Disk injects can be slow, and with large experiments can fail on partition not found errors randomly. An option to use minimega command and control to add config files to VMs and start/restart services as necessary would help alleviate this.

One approach would be to have a flag on a node config to use command and control, and update the AddInject function to schedule c2 accordingly instead of injecting files. However, this alone won't address the issue of needing to restart services after a config has been updated (e.g. networking).

It's likely that apps will have to handle both cases separately.

An additional image subcommand should be added to add miniccc and boot configs to an existing base image, similar to what the cc-dropper app already does.