Remove the header of the auto generated operator pages

[lesquoyb]

Is your request related to a problem? Please describe.
Currently when going to one of the pages that references the operators by alphabetical order, there's a very long part in the beginning that explains how operators work in gama in depth. I think that part should be separated from those file and maybe added somewhere in the "general documentation" and we keep those pages only for the detailed documentation of operators.
It would have many good impacts:

1. As that header also includes sections that list all the operators ordered by category, it "breaks" the search engine by having many times the same operator showing up in all the different pages, which adds confusion to research and also is not very convenient because those are just themselves links to other pages so it adds an operation to every research
2. That documentation seems to be well redacted, but being present in those auto-generated pages makes it less visible to people that would benefit the most of it, as there's low chance they will ever read the top of those huge files.
3. smaller files, it loads faster

Describe the solution you'd like
Move that header somewhere in the general documentation, we could keep a simple link to that page in the header of auto-generated pages if you think it's still important