1.15.5 release

1.15.5 release

- upgrade spring-boot (2.3.12 -> 2.4.13)
- upgrade spring-cloud (Hoxton.SR12 -> 2020.0.6)
- upgrade camunda (7.14.0 -> 7.15.0)
- improve error mapping in OrchestrationRequests class
  by not mapping any exception to 404
- reduce log noise in debug mode by removing probes from the log:
  - introduce logging.request-status.exclusions property to allow
    disabling request logging for certain paths (i.e liveness probes)
    in catalog-db and request-db-adapter
  - disable logging for the scheduled performDnsLookup
  - disable logging for the scheduled checkAllClientsActive

Issue-ID: SO-4195
Change-Id: Ibbb6a34618f768eca5e1e99d6e0bb9c97d95ba13
Signed-off-by: Fiete Ostkamp <Fiete.Ostkamp@telekom.de>