refactor: update AWS Bedrock components descriptions

[edwinjosechittilappilly]

This pull request includes significant updates to the AmazonBedrockEmbeddingsComponent and AmazonBedrockComponent classes to enhance AWS credential handling and configuration options. The changes primarily focus on improving the flexibility and security of AWS credentials management, as well as providing more detailed configuration options for AWS regions and endpoints.

Enhancements to AWS credentials handling and configuration:

• Updated the AmazonBedrockEmbeddingsComponent class to replace aws_access_key and aws_secret_key with aws_access_key_id, aws_secret_access_key, and aws_session_token. Added detailed information for each input to guide users on setting environment variables.
• Added a region_name dropdown input with a comprehensive list of AWS regions and an endpoint_url input to specify the AWS Bedrock endpoint in the AmazonBedrockEmbeddingsComponent class.
• Improved the build_embeddings method in the AmazonBedrockEmbeddingsComponent class to use the new credential inputs and handle session tokens.
• Updated the AmazonBedrockComponent class to include similar changes for AWS credentials and added a model_kwargs input for additional model configuration.
• Enhanced the build_model method in the AmazonBedrockComponent class to use the new credential inputs and added error handling for boto3 session creation.

[codspeed-hq]

CodSpeed Performance Report

Merging #4503 will degrade performances by 90.75%

_{Comparing fix-bedrock-components (9caee68) with main (133a8ae)}

Summary

⚡ 2 improvements
❌ 1 regressions
✅ 12 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	fix-bedrock-components	Change
⚡	test_invalid_run_with_input_type_chat	16.8 ms	15.1 ms	+11.43%
⚡	test_successful_run_with_output_type_any	454.4 ms	399.6 ms	+13.71%
❌	test_successful_run_with_output_type_debug	455.9 ms	4,926.4 ms	-90.75%