few more docs

Hi,

although I might touch these sources again tomorrow, I thought it's good to open a PR in order to receive early feedback (mostly of crude type about missing pieces/paragraphs). Yet, any feedback is welcome :)

tia, F.
no it doesn't, it only explains the bootstrap procedure... point to the other page with alternative approaches here?

This should say:

```
EasyBuild is Python software, so there are a couple of ways to install it. Because of various issues with the
different installation tools that are available for Python packages, we recommend using the **bootstrap**
install procedure described here.

Notes on other ways of installing EasyBuild are available **here**.
```