Install newest Caddy version with role nvjacobo.caddy and update template and pre-generated certs

This commit will also allow Caddy to properly generate certs
with longer lifetimes than 12 hours, and by default it has been set to 1
month. This commit removes the pre-generated certs for safety reasons.
This commit also updates the README.md thoroughly with some
guides about the certs and how to use the role in general.

templates/Caddyfile.j2

@@ -2,6 +2,7 @@
     pki {
         ca local {
             name "My Local CA"
+            intermediate_lifetime 365d
         }
     }
     http_port 8080
@@ -11,6 +12,6 @@
 localhost:8443 {
     acme_server {
         ca local
-        lifetime 720h
+        lifetime 30d
     }
-}
+}