Clean up workflow-designer pom

Clean up workflow-designer pom

- remove all separate dependency declarations of springframework [0]
- update docker base image for init module (2.7-alpine3.8 -> ...3.20)

[0] those should be managed by spring boot. Spring-boot should be updated to
fix vulnerabilities instead of declaring the spring deps separately. The latter
approach can always lead to incompatibilities, like was the case for 1.13.1 + .2
Issue-ID: SDC-4738
Change-Id: I3c629a7c769af974f54ee13d8b3c38c776a6ccc7
Signed-off-by: Fiete Ostkamp <Fiete.Ostkamp@telekom.de>