[DPE-2082] User-friendly output when no primary account is defined

[deusebio]

When no account is found, we produce readable output instead of stacktraces.

Output currently in main

$ spark-client.service-account-registry get-primary
Traceback (most recent call last):
  File "/snap/spark-client/x2/lib/python3.10/site-packages/spark8t/cli/service_account_registry.py", line 181, in <module>
    raise NoAccountFound()
spark8t.exceptions.NoAccountFound

and

$ spark-client.service-account-registry get-config --username=not-existing                                                                                            
Error from server (NotFound): serviceaccounts "not-existing" not found
Traceback (most recent call last):
  File "/snap/spark-client/x2/lib/python3.10/site-packages/spark8t/cli/service_account_registry.py", line 165, in <module>
    maybe_service_account = registry.get(input_service_account.id)
  File "/snap/spark-client/x2/lib/python3.10/site-packages/spark8t/services.py", line 1261, in get
    service_account_raw = self.kube_interface.get_service_account(
  File "/snap/spark-client/x2/lib/python3.10/site-packages/spark8t/services.py", line 727, in get_service_account
    service_account_raw = self.exec(cmd, namespace=self.namespace)
  File "/snap/spark-client/x2/lib/python3.10/site-packages/spark8t/services.py", line 709, in exec
    parse_yaml_shell_output(base_cmd)
  File "/snap/spark-client/x2/lib/python3.10/site-packages/spark8t/utils.py", line 179, in parse_yaml_shell_output
    subprocess.check_output(cmd, shell=True, stderr=None).decode("utf-8")
  File "/usr/lib/python3.10/subprocess.py", line 420, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib/python3.10/subprocess.py", line 524, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command 'kubectl --kubeconfig /home/deusebio/.kube/config  --namespace default  --context microk8s get serviceaccount not-existing -n default -o yaml ' returned non-zero exit status 1.

Output proposed in the PR

$ python -m spark8t.cli.service_account_registry get-primary                       
2023-06-20 10:37:32.000+0200 INFO [spark8t.cli.service_account_registry] (MainThread) (main) Using K8s context: microk8s
2023-06-20 10:37:32.000+0200 WARNING [spark8t.services.K8sServiceAccountRegistry] (MainThread) (get_primary) There are no primary service account available.
2023-06-20 10:37:32.000+0200 ERROR [spark8t.cli.service_account_registry] (MainThread) (<module>) Primary account not found

and

$  python -m spark8t.cli.service_account_registry get-config --username=not-existing
2023-06-20 10:37:47.000+0200 INFO [spark8t.cli.service_account_registry] (MainThread) (main) Using K8s context: microk8s
2023-06-20 10:37:47.000+0200 ERROR [spark8t.cli.service_account_registry] (MainThread) (<module>) Account default:not-existing not found

[grobbie]

Looks good. Small remark but you should tell the user what they could do to resolve the issue in the error message. ie. what command they need to run.