Initial import of Template:interfaceconstants
Initial import of Template:interfaceconstants

https://developer.mozilla.org/en-US/docs/Template:interfaceconstants

Contributors (by MDN username):
* markg
* mnoorenberghe
* trevorh

a2sheppy/kumascript,a2sheppy/kumascript,jpmedley/kumascript,jpmedley/kumascript