Make scenario parsing logic for litmsuctl create scenario command independent of install-chaos-experiments step

[Jonsy13]

Generally the scenario manifests created via Chaos-Center contains an install-chaos-experiments step, which contains definition for all experiments users are going to run as part of that scenario. At the time of implementation of this feature (litmusctl create scenario), it was decided to use install-chaos-experiments step to fetch names of all experiments, users have added in the manifest.

But this can't be always the case, users may not have install-chaos-experiments step in their manifests while scheduling it via litmusctl.

When we upload a manifest in frontend, we had enhanced the logic in frontend by searching for templates which contains kind: ChaosEngine & fetch their names. Since a template containing kind: ChaosEngine denotes a chaos experiment. Same can be done in litmusctl making it independent of install-chaos-experiment.

For reference, how it's done in frontend - https://github.com/litmuschaos/litmus/blob/643f3bffb87a20fee209a77b842ad7eda01d1e54/litmus-portal/frontend/src/utils/yamlUtils.ts#L250

[Jonsy13]

Slack thread for reference - https://kubernetes.slack.com/archives/CNXNB0ZTN/p1669734627249449

[iamnicoj]

This issue can be closed based on PR #114

[Jonsy13]

Thanks @iamnicoj for this enhancement!! This is now released as part of 0.16.0 release of litmusctl.