Ignore secret deletion failures in podman service

[sm453]

At present, the stack manager can fail to start when using podman due to it attempting to delete a secret that does not exist.

A possible work-around would be to ignore any exception thrown whilst deleting secrets:

stack/stack-clients/src/main/java/com/cmclinnovations/stack/services/PodmanService.java

Line 115 in 7072f84

secretsApi.secretDeleteLibpod(oldSecret.getID(), null);