Documentation for environments

[spMohanty]

• Add description about the exact task for each environment
• Add available observations : frames + auxillary in game observations (from observation handlers)
• Add description of the rewards
• Add available Actions
• Replace current static screenshot with a GIF

[spMohanty]

@idvhfd : Did you have a chance to look at this ?

[idvhfd]

@spMohanty I did today and am working on it now.

[idvhfd]

@LorenzoM1997 seems to have started adding actions and descriptions to this while I was doing the same. I couldn't accept his pull request however I have integrated his action lists into the current complete descriptions on branch "documentation".
EDIT: Thanks, @LorenzoM1997! I didn't note you were doing this before dumping my commits, I hope I didn't create any conflicts with your work (I fixed what I could find!).

[LorenzoM1997]

@idvhfd I had already created this to pull in the documentation but then I discovered images aren't currently saved in the repo (or at least I think so). If you want to use it for MazeRunner GIF, you may know where to upload it...

[idvhfd]

@LorenzoM1997 that's actually useful since that's the last thing that needs to be done. It is true that we don't upload directly to the repo, I'll handle this with @spMohanty. Thanks for producing the gif though, it's sweet!