Feature/docs sturcture > Merge issues (#3)

[Daandamhuis]

Hi,

Adjusted the documenter a bit so it generates the files a bit differently, but it's more readable and clean. Especially with a lot of big models at our company the original columns.py would become very huge. This splits the docs per table and that way it is a bit more readable for big models. The index.md still contains the general information about the tables in the model.

Original

model-name
│   index.md
│   measures.md    
│   tables.md    

New setup

model-name
│   index.md
│   measures.md    
└─── tables
│   │   index.md
│   │   sales-orders.md
│   │   article.md
│   │   customer.md
│   │   .....md