Proposal: Allow register_blueprint option to name the Blueprint outside of Flask

Would like to have the option to use a different, more user-friendly name for OpenAPI/Swagger UI Blueprints without needing to change the underlying Flask Blueprint name.

Currently, register_blueprint looks for the name option to be passed in and falls back on Blueprint.name (see: https://github.com/marshmallow-code/flask-smorest/blob/master/flask_smorest/blueprint.py#L180).

Suggestion, something like the below to add a docs_name option to use a different name from the name option, which is also used by the FlaskBlueprint and materially changes the actual route reference that might be used by Flask url_for.

blp_name = options.get("docs_name") or options.get("name", blueprint.name)

If this is an acceptable solution/idea, I can submit a PR. I could be misinterpreting the appropriate place for this change.

Start in flask_smorest/blueprint.py at the register_blueprint implementation referenced by the issue. Review how the current name option is selected, then verify that a separate documentation name can be supplied without changing the underlying Flask Blueprint name or its route references.