Centralize more endpoints in a blueprint

[ppanero]

[might move to flask-resources]

When an application becomes complex, with several endpoints, many times we have to create a resource for just one route. e.g. invenio-draft-resources:

app.register_blueprint(record_bp)
app.register_blueprint(draft_bp)
app.register_blueprint(draft_action_bp)
app.register_blueprint(draft_version_bp)

We might want to provide yes-another-level of abstraction. Sort of as_blueprint(actions=True, version=True) or something like that.