Add a command to bootstrap a livemark/plugin directory

[roll]

Overview

Currently, it just works on empty project livemark start.

We need to use existent Github Templates (rebase livemark/assets/documents/template.md on the Github Templates to avoid duplication)

It should be something like:

livemark draft <dir>

Based on a flag it should be a new livemark repository or a new plugin directory

PS. Take into account Github Templates - can we use it? We definitely need to create a Github Template anyway.