partial docs

[hikalkan]

I'm writing the FluentValidation documentation which includes such a section:

This section is repeated for most of the ABP modules. Instead of copy/paste for all the documentation, such a feature would be nice:

• Allow to include (embed) a document into another document.
• Allow to pass parameters to the inner document. We can reuse the parameter system introduced before. In the partial (inner) document, we can use the parameters for conditional rendering or use their values.