Remove some explicit versions from SO pom

Remove some explicit versions from SO pom

- remove explicit version for spring-web in common pom
  since spring has it's own dependency management and
  having explicit versions leave the risk of incompati
  bilities
- remove explicit spring hal browser version declaration
- bump snapshot version to 1.15.3-SNAPSHOT

Issue-ID: SO-4173
Signed-off-by: Fiete Ostkamp <Fiete.Ostkamp@telekom.de>
Change-Id: I3e9bd1dc5286c109e2a1865e3ca4f328cb6b5717