authenticate: remove extra login page (#34)

- Fixed a bug where Lifetime TTL was set to a minute.
- Remove nested mux in authenticate handlers.
- Remove extra ping endpoint in authenticate and proxy.
- Simplified sign in flow with multi-catch case statement.
- Removed debugging logging.
- Broke out cmd/pomerium options into own file.
- Renamed msicreant cipher to just cipher.

Closes #23

docs/.vuepress/config.js

@@ -24,7 +24,7 @@ function guideSidebar(title) {
 		{
 			title,
 			collapsable: false,
-			children: ["", "docker", "kubernetes", "from-source"]
+			children: ["", "kubernetes", "from-source"]
 		}
 	];
 }