feat(bedrock): add bedrock custom models, customization jobs, provisioned throughput and logging configuration

[npellegrin]

Closes #160

[npellegrin]

I have not tested this part on real infrastructure for now. Will try to write some unit tests 😃

The current GO SDK version prevent implementing Bedrock Guardrails and Bedrock Evaluation Jobs, I will put it in another PR to have this one green.

[ekristen]

Mocks would be a good place to start. I do have examples of integration tests that require full AWS credentials to run.

Look for _mock_test.go for mock related on how to create the mocks for the service. Writing mocks requiring some additional alterations to the source. Ideally since this is net new we want to run against real resources too or at least get real outputs back from the API to create the mocks to ensure we have proper coverage.

[ekristen]

@npellegrin are you going to have time to finish this up or should we close it for the time being?