Missing link for Advanced Project Template in Guide

[mtangoo]

To experience the problem

1. Open docs
2. Click Guide
3. Click Special Topics
4. Click Advanced Project Template

[cebe]

there is a link to the readme file on github:

* [Advanced Project Template](https://github.com/yiisoft/yii2-app-advanced/blob/master/docs/guide/README.md)

https://github.com/yiisoft/yii2/blob/master/docs/guide/README.md

website docs are currently not up to date, will fix that when I find time for it.

[mtangoo]

FYI I did build them using script from yiisoft/yii2/issues/3267

[cebe]

Now I see the problem, need to adjust the guide to behave well with external links...

[mtangoo]

Thats great. I hope to get time that I help with docs.
I see few TBD on guide!