Consider adding default templates to cli

[mfridman]

(Really excited about this project!)

The idea of being able to use your own templates is neat, however, when starting out it may be easier (and more manageable) to use a default (built-in) template if one is not supplied, at least for the supported server/client: Go and ES6.

I don't want to keep a copy of server.go.plush or client.go.plush within our repo. From day-to-day I'd update the remoto cli (if needed) and use it to generate source code without worrying about templates.

remoto project.remoto.go go-server -o server.go

go-server go-client es6-client etc. otherwise check for the supplied template path.