FE: Support awsRoleArn when using IAM Auth

[ankitk-me]

• Breaking change? (if so, please describe the impact and migration path for existing application instances)

What changes did you make? (Give an overview)
Added support for the optional awsRoleArn configuration when using IAM authentication.

Is there anything you'd like reviewers to focus on?
In addition to awsRoleArn, I have also added awsRoleSessionName & awsStsRegion as defined here in MSK IAM Auth Library.

sasl.jaas.config=software.amazon.msk.auth.iam.IAMLoginModule required awsRoleArn="arn:aws:iam::123456789012:role/msk_client_role" awsRoleSessionName="producer" awsStsRegion="us-west-2"; 

Docs PR: kafbat/ui-docs#61

How Has This Been Tested? (put an "x" (case-sensitive!) next to an item)

• No need to
• Manually (please, describe, if necessary)
• Unit checks
• Integration checks
• Covered by existing automation

Checklist (put an "x" (case-sensitive!) next to all the items, otherwise the build will fail)

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (e.g. ENVIRONMENT VARIABLES)
• My changes generate no new warnings (e.g. Sonar is happy)
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged

Check out Contributing and Code of Conduct

A picture of a cute animal (not mandatory but encouraged)

[github-actions]

Hi ankitk-me! 👋

Welcome, and thank you for opening your first PR in the repo!

Please wait for triaging by our maintainers.

Please take a look at our contributing guide.

[Haarolean]

Hi, thanks for the PR. Does everything work with these changes?

[ankitk-me]

@Haarolean yes works as expected. I was able to create a local docker image and validate these changes.

[Haarolean]

@ankitk-me thank you!