Display the invocation environment to aid debugging

[davidemyers]

This change adds a script that gets called from Ansible early on during a deployment to print out information intended be helpful when included by a user when reporting an issue. It attempts to detect the operating system and currentness of the Algo software, as well as display various Ansible variables.

Sample output when called from Ansible:

TASK [Gathering Facts] *************************************************************************************************
ok: [localhost]

--> Please include the following block of text when submitting issues:

Algo running on: Ubuntu 18.04.1 LTS
Created from git fork. Last commit: 4c70b71 Fix spacing in congrats message (#1104)
Python 2.7.15rc1
Runtime variables:
    algo_provider "digitalocean"
    algo_ondemand_cellular "False"
    algo_ondemand_wifi "True"
    algo_ondemand_wifi_exclude ""
    algo_local_dns "False"
    algo_ssh_tunneling "False"
    algo_windows "False"
    wireguard_enabled "True"
    dns_encryption "True"

TASK [Display the invocation environment] ******************************************************************************
changed: [localhost -> localhost]

Sample output when run directly:

Algo running on: Mac OS X 10.12.6
ZIP file created: Sep  2 15:26:06 2018
env/bin/python not found: has 'python -m virtualenv ...' been run?

I'm not very proficient with Ansible and may not have done everything properly. Please review for correctness.

[jackivanov]

Pretty good idea, thanks!