Parse input from a file without json-c

[dlrobertson]

We should allow the batch processing of sub-commands from a file without having to use json. For example, the following

sylkie -x /path/to/file

Where file contains

ra --interface=ens3 \
    --target-mac=52:54:00:e3:f4:06 \
    --router-ip=fe80::b95b:ee1:cafe:9720 \
    --prefix=64 \
    --repeat=-1 \
    --timeout=10
ra --interface=ens3 \
    --target-mac=52:54:00:c2:a7:7c \
    --router-ip=fe80::cbed:6822:cd23:bbdb \
    --prefix=64 \
    --repeat=-1 \
    --timeout=10

Should be the same as passing the filename of a file containing the following to the -j command.

{
    "ra": [
        {
            "interface": "ens3",
            "target-mac": "52:54:00:e3:f4:06",
            "router-ip": "fe80::b95b:ee1:cafe:9720",
            "prefix": 64,
            "repeat": -1,
            "timeout": 10
        },
        {
            "interface": "ens3",
            "target-mac": "52:54:00:c2:a7:7c",
            "router-ip": "fe80::cbed:6822:cd23:bbdb",
            "prefix": 64,
            "repeat": -1,
            "timeout": 10
        }
    ]
}