fix(back-end): implementation of security better

backend/src/main/resources/application.properties

@@ -7,6 +7,7 @@ spring.datasource.username=${DB_USERNAME:printcalc}
 spring.datasource.password=${DB_PASSWORD:printcalc_secret}
 spring.jpa.hibernate.ddl-auto=update
 spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect
+spring.jpa.open-in-view=false
 
 
 # Slicer Configuration
@@ -47,3 +48,6 @@ admin.password=${ADMIN_PASSWORD}
 admin.session.secret=${ADMIN_SESSION_SECRET}
 admin.session.ttl-minutes=${ADMIN_SESSION_TTL_MINUTES:480}
 admin.auth.trust-proxy-headers=${ADMIN_AUTH_TRUST_PROXY_HEADERS:false}
+
+# Expose only liveness endpoint by default.
+management.endpoints.web.exposure.include=health