config: enable internal HTTPS in Caddyfile and add documentation screenshots

- Enabled `tls internal` in `Caddyfile` for secure communication behind the proxy.
- Added new screenshots to `docs/ScreenShots` for deployment, application settings, and error diagnosis.

Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>

config/docker/caddy/web-app/Caddyfile

@@ -1,6 +1,5 @@
 {
 # Global Options
-# Enable Prometheus metrics
   servers {
             metrics
           }
@@ -10,6 +9,9 @@
 # Root directory for static files
   root * /usr/share/caddy
 
+# Enable internal-only HTTPS for secure communication behind the proxy
+  tls internal
+
 # Access Logs (JSON format for Docker)
   log {
         output stdout