Dead links in tutorial

[gudlot]

Hi EasyReflectometry-Team,

I am reading a tutorial about EasyReflectometry. In the section "building our model" https://docs.easyreflectometry.org/simple_fitting.html#Building-our-model several links are dead.

For example:
https://www.reflectometry.org/isis_school/2_model_dependent_analysis/what_is_model_dependent_analysis.html
gives an error 404: Not found.