Fix: cannot import `utils`, fix with boto3, bedrock client and runtime, improve docs

[Dinuda]

Issue #, if available:

Description of changes:

1. Add clear instructions on how to setup aws service role, cli user and user profile.
2. Fix: from utils import bedrock - There was no library named utils, there is no pip package for bedrock utils, to make it work you need to manually copy paste files into site_packages. Ref: Issue 31
   • use 'boto3.client()` instead
3. According to instructions from Issue 31, the utils do not contain invoke_model.
   • use boto3.runtime() -bedrock_runtime = boto3.client('bedrock-runtime') By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[Dinuda]

Hi guys 👋 , can I get a review on this?

[w601sxs]

Closing this based on new updates and testing on the latest workshop - https://github.com/aws-samples/amazon-bedrock-workshop. Please do resubmit if it still exists in the new workshop.