test(inspec): share library to access some minion informations

The `system.hostname` return the result of either `hostname -s` or
`hostnamectl --static` depending of the availability of each command.

The `system.platform` return a hash with tweaked `inspec.platform`
values:

- `system.platform[:family]` provides a family name for Arch
- `system.platform[:name]` modify `amazon` to `amazonlinux`
- `system.platform[:release]` tweak for Arch and Amazon Linux:
  - `Arch` is always `base-later`
  - `Amazon Linux` release `2018` became `1`
- `system.platform[:finger]` is just the concatenation of the name and
  the first release number (except for Ubuntu which gives `20.04` for
  example)

test/integration/share/inspec.yml

@@ -0,0 +1,18 @@
+# -*- coding: utf-8 -*-
+# vim: ft=yaml
+---
+name: share
+title: Inspec shared resources
+maintainer: SaltStack Formulas
+license: Apache-2.0
+summary: shared resources
+supports:
+  - platform-name: debian
+  - platform-name: ubuntu
+  - platform-name: centos
+  - platform-name: fedora
+  - platform-name: opensuse
+  - platform-name: suse
+  - platform-name: freebsd
+  - platform-name: amazon
+  - platform-name: arch