NanoRC conf svc

[plasorak]

With this PR, nanorc serves the configuration over the network rather than relying on a shared file system. This should work with and without k8s and no matter if the configuration was uploaded to the MongoDB configuration service.

There is also quite a bit of refactoring in cfgmgr.py, that code still is... not great.

I suggest testing this the following way:

• running nanorc with ssh
• same as above with a partition offset
• uploading the configuration to MongoDB and running ssh nanorc with db://config-name as the name of the configuration
• same as above with a partition offset
• running nanorc with k8s
• same as above with a partition offset
• uploading the k8s configuration to MongoDB and running k8s nanorc with db://config-name as the name of the configuration
• same as above with a partition offset
• running 2 DAQ subsystems (with a topjson) using ssh
• running 2 DAQ subsystems (with a topjson) using k8s

[TiagoTAlves]

All functionality was tested and everything works as expected, both in k8s and ssh.