Clojurians Log v2

I've added a bunch of new libraries for Duct: • https://github.com/duct-framework/file.temp - create temp files/dirs that last until the system is halted • https://github.com/duct-framework/database.datalog - generic protocols for accessing Datomic-like databases • https://github.com/duct-framework/database.datalog.datalevin - Integrant methods for Datalevin • https://github.com/duct-framework/module.datalog - convenient defaults for Datomic-like databases