Low sub message

New template to display message when submission queue is low.  Both the message and the limit live in the vars table. Need to run these commands on the production DB when adding this code.

INSERT INTO vars (name, value, description) VALUES ('subs_level','15','Level at which to not to display low submissions message');
INSERT INTO vars (name, value, description) VALUES ('subs_message','SoylentNews is powered by your submissions, so send in your scoop.','Messaged displayed when submission queue is low');