Add TFlops calculator and stuck job monitor

[emeraldbay]

Issue #, if available:

Description of changes:

1/. Add training job TFlops calculator

2/. Add stuck job monitor, customer can monitor specific Cloudwatch log stream output specified. If customer did not see the expected output in Cloudwatch log stream for a while, we know the training job is stuck and act accordingly.

Testing done:

Merge Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your pull request.

General

• [X] I have read the CONTRIBUTING doc
• [X] I used the commit message format described in CONTRIBUTING
• [X] I have used the regional endpoint when creating S3 and/or STS clients (if appropriate)
• [X] I have updated any necessary documentation, including READMEs

Tests

• [X] I have added tests that prove my fix is effective or that my feature works (if appropriate)
• [X] I have checked that my tests are not configured for a specific region or account (if appropriate)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.