Add option to create clojure file (namespace)

[afucher]

Is your feature request related to a problem? Please describe.
When need to create a new clojure file it does not have the proper action, so need to create a generic file with clj extension. This could lead to errors while using - instead of _ on file names.

Describe the solution you'd like
Have a dedicated action to create clojure files (namespace) with proper validation on name.