Implementation of #402 +species informations

[Jarakoto]

Add a "describe" gama server command to get a model description which gives :

• The species names and related actions
• The experiments and related parameters

[Jarakoto]

I would like to divide the nested for loops to the related interface, but it will be used only in the gama server part.

[lesquoyb]

Hello and thank you for your contribution!
So far the code seems good, but before merging I think we should pay attention to those points:

• Check that the command works when gama has a GUI
• Check that the command works when gama is in headless server mode
• Add parameters to only get the information that we care about (species, actions, parameters etc.) instead of everything
• Add a description of the command on the online documentation:
  • general description of what it does
  • parameters needed and optional to call it
  • format of the output
  • possible errors
• If possible try to comply with codescene quality gates (I haven't checked it yet, sometimes there is just no proper way to do it) => has been improved enough, the rest to do has been identified and tranfered to Refactor, polish and document gama-server and its API #1
• @AlexisDrogoul This command as well as the load command (and maybe other ones ?) are compiling the model, do you think there's a "clean" way to store the compiled model to avoid possible recompilation that could be long and resource intensive ? =>won't be done

[lesquoyb]

Hello @Jarakoto, I have a commit to fix a few minor issues with this PR but I cannot push it because (I think) it is hosted on your github and you have to allow external contribution, here is an example pull request with the same problem:

It's the checkbox at the bottom right corner: "allow edits by maintainers"

[Jarakoto]

Hello @lesquoyb,
Thank you for the the review and the fixes. I wasn't able to see the fix (the PR panel was empty so this checkbox was not displayed). I added you as maintainer of this repo, are you able to push on it ?

[lesquoyb]

So I thought a bit about compiling only once, but finally I don't think it's a good idea as the describe command is independent from loading or not the model, and technically it could be "normal" in certain cases for the model file to be updated in between calls. So for now let's forget about it.

Regarding passing the quality gates of codescene, the only thing left would be to refactore the code for compilation (but not cache it) between describe and load and we should pass it. That being said I prefer to add that task to the issue dedicated to refactoring gama-server in general (#1), as it may be a little bit tricky and out of the scope of this PR.

I've just created a draft of documentation for the new command that you can see here and if you think it's clear enough and I didn't miss anything then we can merge that PR.

[Jarakoto]

@lesquoyb Thanks a lot for the improvement of the function. It's all good for me.
I would refine the last sentence of the documentation to : "If certain information is requested to be ignored via a parameter (as explained above), the corresponding field(s) will be omitted from the response."

[lesquoyb]

Sounds good to me