[BUG][DocBot] Need exceptions in custer_bootstrap.py

[dtaivpp]

What is the bug?

In our cluster_bootstrap.py we should be raising the appropriate exceptions instead of printing errors when we come across them. Additionally we will need to wrap the main block in a try except to handle those accordingly. https://github.com/opensearch-project/demos/pull/60/files#r1368888960

What is the expected behavior?

Anytime a function fails we expect it to raise an exception rather than silently failing.

Do you have any additional context?

N/A

[LucasWang750]

I would like to work on this issue

[dtaivpp]

Closed with #70