Fail fast by checking if playbook exists earlier for `ansible-navigator run`

[brookelew]

ISSUE TYPE

• Feature Idea

SUMMARY

Currently, ansible-navigator run <playbook> does a lot of setup tasks before failing to run if the playbook does not exist. If we do this check earlier, we can save some time, especially an expensive pull of the EE image, which is particularly useful in CI pipelines/non-persistent environments.