planning#2251 : Send large submission data as attachment

See merge request !434

fix(deps): update dependency ch.qos.logback:logback-classic to v1.5.8

See merge request !437

# Conflicts:
#	client/src/main/java/dev/fitko/fitconnect/api/config/ApplicationConfig.java
#	client/src/main/resources/schema-config.yaml
#	client/src/test/java/dev/fitko/fitconnect/core/schema/SchemaResourceProviderTest.java
#	client/src/test/java/dev/fitko/fitconnect/core/validation/DefaultValidationServiceTest.java
#	integration-tests/src/test/java/dev/fitko/fitconnect/integrationtests/IntegrationTestBase.java
#	integration-tests/src/test/java/dev/fitko/fitconnect/integrationtests/ReplyIT.java
#	integration-tests/src/test/java/dev/fitko/fitconnect/integrationtests/SenderClientIT.java

planning#2223: DeutschlandID Reply Channel

See merge request !429

refactor: add default additional reference info object that can be extended with optional fields (planning#2251)

refactor: hide buffer helper and introduce explicit attachment method to handle submission data (planning#2251)

fix(deps): update dependency org.yaml:snakeyaml to v2.3

See merge request !435

test: make test more stable by requesting only the submissions that were actually sent (planning#2251)