Speed up compilation

[SudeshnaBora]

Related to #179

[denisalevi]

1. You seem to have used the version that was used for the consistency tests (that means with TimedArray implementations of the randomness). Not sure what the effect is on compile times due to curand etc.
2. And it seems you used a different script for brian2genn? In fact, you used one without TimedArray for brian2genn? You need to use the exact same script if you want to make things comparable.
3. Please don't add large files to the repository. This PR tried to add 80MB of files to this repository, which doubles the current repository size. This just makes things super slow. Most of the size comes from the arrays saved in all the results directory. Those you don't need at all, please don't add them to the repository. And the TimedArray implementations store the arrays in the static_arrays folders. Those alone take up 20MB.

TODOs:

1. How much work is it to repeat the merge for a script that doesn't use TimedArrays? If you think this is done in ~10min, please do that. If you have to manually merge everything again, just leave it as is. Then we will just not merge the branch.
2. Either way, please make sure that the script for brian2cuda and brian2genn are the same (either brian2cuda without TimedArray or brian2gen with TimedArray)
3. If you got rid of the TimedArrays, please create a new PR where only source files are added (no resulst folders). If recreating the script without TimedArray takes too much time, don't worry about this. We won't merge this PR in that case.