* add nginx to load balancing nav menu and fix bullets
* fill out nginx lb guide
* formatting
* change Nginx to NGINX
* add step to verify load balancer config
* update docker image and web app output
* change Nginx to NGINX in main load balancing page
* modify change signal to SIGHUP and add else condition in template stanza to prevent nginx from crashing when no services are available to load balance
* add note about external load balancer
* clarifications and link to reference architecture
- Revised "What is Nomad" copy
- Added "Key Features" section with links to task drivers & device plugins with lift-and-shift from README
- Added "Who Uses Nomad" section with users, talks, blog posts
- Removed Hadoop YARN, Docker Swarm, HTCondor from comparisons
- Revamped Guides section
- Inserted "Installing Nomad", "Upgrading", "Integrations" as persistent in Guides navbar
- Split Installing Nomad into two paths for users (one for Sandbox with "Quickstart", one for Production)
- Surfaced "Upgrading" and "Integrations" section from documentation
- Changed "Job Lifecycle" section into "Deploying & Managing Applications"
- Reworked "Operations" into "Operating Nomad"
- Reworked "Security" into "Securing Nomad"
- Segmented Namespaces, Resource Quotas, Sentinel into "Governance & Policy" subsection
- Reworked "Spark integration" into its own "Analytical Workloads" section
* add load-balancing guide
* restructure load balancing section
* defining consul lb strategies inline and giving fabio its own bullet point
* update docker image name and shorten job template
* changing system scheduler link to relative link and moving load balancing navigation link right to right above Web UI
