docs: re-introduce usage/cli/examples

Splitting the content in multiple sub-sites broke links.
By keeping it hidden, this site serves as a soft-redirect
landing page.

The user won't immediately find the information an external
site might have hyperlinkes, but a short summary of gives
the user a fast overview on where to continue.

docs/content/usage/cli/examples.md

@@ -0,0 +1,30 @@
+---
+title: Examples
+date: 2019-03-03T16:39:46+01:00
+draft: false
+hidden: true
+---
+
+{{% notice note %}}
+**Heads up!** We've restructured the content a bit.
+{{% /notice %}}
+
+You'll find the content now at one of these pages:
+
+- Guide: [**How to obtain a certificate**]({{< ref "usage/cli/Obtain-a-Certificate" >}})
+  - Using the built-in web server
+  - Using a DNS provider
+  - Using a custom certificate signing request (CSR)
+  - Using an existing, running web server
+  - Running a script afterward
+  - Use case
+- Guide: [**How to renew a certificate**]({{< ref "usage/cli/Renew-a-Certificate" >}})
+  - Using the built-in web server
+  - Using a DNS provider
+  - Running a script afterward
+  - Automatic renewal
+- Reference: [**Command line options**]({{< ref "usage/cli/Options" >}})
+  - Usage
+  - Let's Encrypt ACME server
+  - Running without root privileges
+  - Port Usage