docs: log session outcomes and apply enhancements across multiple components

- **Docker Fixes:** Resolved failed builds for Gateway and Ping services by switching to `eclipse-temurin:21-jdk-alpine`, correcting Gradle configurations, and fixing cache mount paths.
- **ZNS-Import Consul Registration:** Enabled Consul service discovery by updating `application.yaml` and `build.gradle.kts`.
- **pgAdmin Provisioning:** Preconfigured the database server in `servers.json` and updated `dc-ops.yaml` for seamless setup.
- **Postman Documentation:** Added a detailed Postman test guide covering environment setup, endpoint groups, and recommended test sequences.

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

config/docker/pgadmin/servers.json

@@ -0,0 +1,14 @@
+{
+  "Servers": {
+    "1": {
+      "Name": "Meldestelle PostgreSQL",
+      "Group": "Meldestelle",
+      "Host": "postgres",
+      "Port": 5432,
+      "MaintenanceDB": "pg-meldestelle-db",
+      "Username": "pg-user",
+      "SSLMode": "prefer",
+      "Comment": "Haupt-Datenbank für die Meldestelle-Applikation"
+    }
+  }
+}