Supporting nested list arguments in input strings

input: "url=http://foobar.com/justin,args=foo,args=justin,otherKey=AnotherKey,finalKey=42"
Expected output in raxmon-cli/utils.str_to_dict(input)
{
    "url": "http://foobar.com/justin",
    "args": ["foo", "justin"],
    "otherKey": "AnotherKey",
    "finalKey": "42"
}

Currently, args is parsed as "justin", overriding "foo".