refactor: standardize environment variable naming and add PING_SERVICE_URL configuration

Aligned environment variable naming across backend and infrastructure files for improved consistency (e.g., `SPRING_CLOUD_CONSUL` and `SPRING_SECURITY_OAUTH2_RESOURCESERVER`). Introduced `PING_SERVICE_URL` to support dynamic Ping-Service routing. Updated Docker Compose health checks, profiles, and memory settings for scalability and stability.

backend/services/ping/ping-service/src/main/resources/application.yaml

@@ -1,6 +1,6 @@
 # Port, auf dem das Ping-Service läuft
 server:
-  port: ${PING_SERVICE_PORT:8082}
+  port: ${PING_SERVER_PORT:8082}
 
 spring:
   application:
@@ -24,7 +24,7 @@ spring:
 
   flyway:
     enabled: true
-    # Erlaubt Migration auch wenn DB nicht leer ist (wichtig für Dev)
+    # Erlaubt die Migration, auch wenn DB nicht leer ist (wichtig für Dev)
     baseline-on-migrate: true
     # Sucht standardmäßig in classpath:db/migration
 
@@ -33,13 +33,13 @@ spring:
       resourceserver:
         jwt:
           # Keycloak URL (lokal via Port Forwarding)
-          issuer-uri: ${KEYCLOAK_ISSUER_URI:http://localhost:8180/realms/meldestelle}
-          jwk-set-uri: ${KEYCLOAK_JWK_SET_URI:http://localhost:8180/realms/meldestelle/protocol/openid-connect/certs}
+          issuer-uri: ${SPRING_SECURITY_OAUTH2_RESOURCESERVER_JWT_ISSUER_URI:http://localhost:8180/realms/meldestelle}
+          jwk-set-uri: ${SPRING_SECURITY_OAUTH2_RESOURCESERVER_JWT_JWK_SET_URI:http://localhost:8180/realms/meldestelle/protocol/openid-connect/certs}
 
   cloud:
     consul:
-      host: ${CONSUL_HOST:localhost}
-      port: ${CONSUL_PORT:8500}
+      host: ${SPRING_CLOUD_CONSUL_HOST:localhost}
+      port: ${SPRING_CLOUD_CONSUL_PORT:8500}
       enabled: ${CONSUL_ENABLED:true}
       discovery:
         enabled: ${CONSUL_ENABLED:true}