Add startup probes to Onlyoffice, remove initialDelaySeconds

Deployment of OO fails often because the container hits the live-/readyness limits. The logs show this:

root@ci-399-helmreleases-test:~# kubectl -n oas-apps logs nc-onlyoffice-documentserver-74f5f66c7c-57wbw -f
psql:/var/www/onlyoffice/documentserver/server/schema/postgresql/createdb.sql:20: NOTICE:  relation "doc_changes" already exists, skipping
psql:/var/www/onlyoffice/documentserver/server/schema/postgresql/createdb.sql:36: NOTICE:  relation "task_result" already exists, skipping
-e Generating fonts and themes, please wait...
Generating presentation themes, please wait...Done

And the events:

Events:
  Type     Reason     Age                   From                               Message
  ----     ------     ----                  ----                               -------
  Normal   Scheduled  18m                   default-scheduler                  Successfully assigned oas-apps/nc-onlyoffice-documentserver-74f5f66c7c-57wbw to ci-399-helmreleases-test
  Normal   Killing    10m                   kubelet, ci-399-helmreleases-test  Container nextcloud-onlyoffice failed liveness probe, will be restarted
  Normal   Pulling    9m22s (x2 over 18m)   kubelet, ci-399-helmreleases-test  Pulling image "infrarednetwork/onlyoffice-documentserver:5.4.0-2-1"
  Normal   Pulled     6m56s (x2 over 13m)   kubelet, ci-399-helmreleases-test  Successfully pulled image "infrarednetwork/onlyoffice-documentserver:5.4.0-2-1"
  Normal   Created    6m55s (x2 over 12m)   kubelet, ci-399-helmreleases-test  Created container nextcloud-onlyoffice
  Normal   Started    6m54s (x2 over 12m)   kubelet, ci-399-helmreleases-test  Started container nextcloud-onlyoffice
  Warning  Unhealthy  4m54s (x4 over 10m)   kubelet, ci-399-helmreleases-test  Liveness probe failed: Get http://10.42.0.16:8000/welcome: dial tcp 10.42.0.16:8000: connect: connection r$
fused
  Warning  Unhealthy  3m12s (x17 over 12m)  kubelet, ci-399-helmreleases-test  Readiness probe failed: Get http://10.42.0.16:8000/welcome: dial tcp 10.42.0.16:8000: connect: connection $
efused

Font and theme generation takes a long time, we could Generate fonts and themes during build, not during startup. But meanwhile we need to increase the probe timeouts.