Usage docs (#501)

* Add setup and usage docs

Signed-off-by: lucperkins <lucperkins@gmail.com>

* Finish initial version of setup doc

* Add YAML config file for CLI docs

* Finish CLI shortcode

Signed-off-by: lucperkins <lucperkins@gmail.com>

* Fix scrolling on mobile

Signed-off-by: lucperkins <lucperkins@gmail.com>

* Finish first version of usage doc

Signed-off-by: lucperkins <lucperkins@gmail.com>

* Remove go install section, modify CSS for CLI docs, and fix typo

Signed-off-by: lucperkins <lucperkins@gmail.com>

website/layouts/partials/docs/main.html

@@ -2,7 +2,7 @@
   {{ partial "docs/header.html" . }}
 
   <section class="section">
-    <div class="content is-medium">
+    <div class="content">
       {{ .Content }}
     </div>
   </section>