Add content on performance benchmarks.

[khushi-411]

This PR adds content on performance. Follows issue: #370

Please have a look. Thanks!

Rendered markdown link (for ease of readability): https://github.com/khushi-411/numpy.org/blob/master/content/en/benchmark.md

Future work which should be added here according to me are:

• Algorithms: Classification of Algorithms. Here, I classified it into 5 categories (Transonic jit, Transonic boost, Numba, NumPy, Pure NumPy). Future aims will be to update this into Cython, Pythran, Numba, TransonicJit, Transonic boost, Transonic Cython is any other relevant algorithms that I'm presently not sure about.
• Graphs: Do we need to iterate over different datasets? We can just select any one or two datasets and the number of times those algorithms are to be implemented and then plot the graph. Does it sound viable?
• Content: Improve Documentation (Include introduction). I mentioned various libraries in the post. Is that needed? I think that it can be presented in a better way. What do you think about how can I improve it?
• Code Quality: Profile code and optimize it.

cc: @mattip

[rgommers]

Thanks for working on this @khushi-411! Looks like a good start.

[rgommers]

This probably belongs in the caption of the graph. With a bit more details about the exact CPU. For example:

$ cat /proc/cpuinfo | grep Intel

And then slightly reformat like: Intel i9-7920X @ 2.90GHz

[khushi-411]

Apologizes, I will update that. Thanks!

[rgommers]

Linking to your own repo is fine for now. We can make it a separate NumPy repo or put the scripts in an existing repo somewhere, when you are closer to done with this PR.

[khushi-411]

Sure definitely, these are just sample codes. I feel that these need to be improved, and once it's finalized, we can create a repo or update somewhere in the existing repo as you'll wish. Thanks!

[rgommers]

I'm thinking what should come next is indeed a comparison with C/C++ and Fortran, like this sentence says?

The accelerators can be a second part of the story.

[mattip]

The text should explain that this is a numerical simulation of the N-body problem and giv ethe constraints of the problem

C/C++ and Fortran code simulations can be found in the original repo https://github.com/paugier/nbabel/

[rgommers]

It would be better to commit the figure in this PR. The place to put it is static/images/content_images/