fix response header when lambda function returns errorMessage

[ezequielm]

What did you implement:

Closes #101

How did you implement it:

When lambda function returns an errorMessage (that means the function handle the error) the invoke/local not reject the promise and registry/invoke set the correct header (X-Amz-Function-Error) for response of lambda invoke

How can we verify it:

1. Go to examples folder, and start simulating lambda
2. Open a new terminal and run aws lambda invoke --function-name docker-dev-lambdaError outfile.txt --endpoint-url http://localhost:4000

Todos:

• Write tests
• Write documentation
• Fix linting errors
• Provide verification config/commands/resources
• Change ready for review message below

Is this ready for review?: YES