Adding Documentation for Enabling External Authentication

Adding ManageIQ/Guides for installing and enabling
external authentication via IPA.
PR Review Changes to the External Authentication Guide.
Updating REST API Reference to mention Request Tasks

- For completeness and reflecting the /api/request_tasks collection.
Merge pull request #24 from abellotti/rest_api_request_tasks

Updating REST API Reference to mention Request Tasks
Merge pull request #21 from abellotti/external_auth

Adding Documentation for Enabling External Authentication
Reformat coding standards to bring line lengths under 80 characters
Take into account Jason Frey's feedback - indent bullet list items that
wrap to multiple lines to align with 1st letter of next line
Do not indent inside code blocks
Create Proposals directory

Added directory.
Copied files from private location here.
remove files not suitable for publishing
keep one good example of a proposal
Merge pull request #12 from dneary/reformat_docs

Reformat coding standards to bring line lengths under 80 characters (2nd try)
Merge pull request #25 from mfeifer/proposals

Create Proposals directory
Updates after the end of Sprint 9
Merge pull request #26 from chessbyte/sprint_9_end

Updates after the end of Sprint 9
Add Configuration Redesign Proposal from old CFME wiki.
REST API Provisioning/Automate Proposal

Proposal to introduce:
- /api/provision_requests
- /api/automation_requests
Merge pull request #27 from Fryguy/configuration_redesign_proposal

Add Configuration Redesign Proposal
Merge pull request #28 from abellotti/rest_api_automate_proposal

REST API Provisioning/Automate Proposal
Updated REST API Reference Guide for Automation API's

Added examples for:
Provisioning requests @ /api/provision_requests
Automation requests @ /api/automation_requests
Merge pull request #29 from abellotti/rest_api_automate

Updated REST API Reference Guide for Automation API's
don't complain for aligning code
Merge pull request #30 from jrafanie/rubocop_align_args

don't complain for aligning code
REST API Reference Guide update to reflect Service Requests as subcollection

- Supporting /api/service_templates/#/service_requests
- Supporting /api/service_templates/#/service_requests?expand=resources,request_tasks
- Supporting /api/service_requests/#/request_tasks (or tasks)