fix(fullstack): Use platform linux/amd64 for image building, some env var fixes

legalconsenthub-backend/src/main/resources/application.yaml

@@ -3,11 +3,10 @@ spring:
     name: legalconsenthub
 
   datasource:
-    hikari:
-      auto-commit: false
-    url: jdbc:h2:mem:legalconsenthub-database
-    username: user
-    password: pw
+    auto-commit: false
+    url: ${LEGALCONSENTHUB_DB_URL}
+    username: ${LEGALCONSENTHUB_DB_APP_USER}
+    password: ${LEGALCONSENTHUB_DB_PASSWORD}
 
   jpa:
     show-sql: true
@@ -36,5 +35,5 @@ spring:
     oauth2:
       resourceserver:
         jwt:
-          issuer-uri: http://localhost:7080/realms/legalconsenthub
-          jwk-set-uri: http://localhost:7080/realms/legalconsenthub/protocol/openid-connect/certs
+          issuer-uri: ${SPRING_SECURITY_OAUTH2_RESOURCESERVER_JWT_ISSUER_URI}
+          jwk-set-uri: ${SPRING_SECURITY_OAUTH2_RESOURCESERVER_JWT_JWK_SET_URI}