Add --name option to create plugin

[flomotlik]

Feature Request:

With serverless create -t aws-nodejs --name my_service you should be able to automatically overwrite the name of the created service

Benefits:

• Make it easier for users to set the name and not run into an issue when the name is set to the default name

Linked Issues:

• Creating a service with 1.0.0-alpha.2 completely ignores the --name parameter/option and uses "aws-nodejs" instead  #1616

[lamroger]

Would love feedback on the possible approaches here #1910

[pmuens]

Closing this as a PR (#1910) was opened for this one. We'll continue the discussion there.