Optimize InSpec detect

[chris-rock]

We could enrich the inspec detect command with more valuable information. Currently we recieve the following output:

$ inspec detect
{"name":"mac_os_x","family":"darwin","release":"10.10.5","arch":null}

Especially the family does not reflect the power inspec offers with methods like os.linux? or os.redhat?. Therefore I propose to return an array for family. This returns all tags for an operating system like

{
    "name":"mac_os_x",
    "release":"10.10.5",
    "arch":null,
    "family":["darwin", "unix"]
}

{
    "name":"centos",
    "release":"7",
    "arch": "x86",
    "family":["linux", "unix", "redhat"]
}

We also should think about:

• Users are confused by the json output that may return null.
• We should have a json and human-readable output analog to the --format for exec (maybe even reuse those formatters), as highlight in a previous iteration of this issue by @arlimus

A human-readable output may look like

Operating System: Windows
Release:           2012 R2
Arch:                 X68

[arlimus]

all in all, love the idea!

Could we do:

inspec detect
... as suggested ...

inspec detect --format json
{ ... }

Moreover, this includes a sub-issue which must be treated as well: not returning null/nil.
For this case, a suggestion for output would be:

Operating system detection failed

and

{}

[arlimus]

btw: this will break chef-compliance 😉 we'll need to update that too

[arlimus]

Great update, cheers @chris-rock !