Add doc directory

When u create service you need to write documentation about it. It's good practice and one point to the karma :). It will be great if `create-aio-app` quickly provides a way to do this.

So, what need to do:

- [x] create doc directory (use sphinx for that)
- [ ] write description about:
- [ ] about the project's architecture
- [ ] developing
- [ ] testing
- [x] add command to make file for generate docs
- [x] publish this doc using github's pages or some else
- [x] add auto deploy docs for each release or push into master