Improve the place-holder page at the ".com" domain

[GaelVaroquaux]

I have added a very pretty basic page to give a warning for people visiting our ".com" domain, rather than the ".org" domain (purposely not linking here, to avoid increasing the page rank of this page):
https://github.com/scikit-learn/scikit-learn.com

I used a very basic and empty hugo theme. My gut feeling is that we want very little here because we do not want people to link here. For this reason, I did not do a redirect in any way.

The number one purpose of owning this domain name is to avoid typosquatting on it.

I think that the comm's team should have a quick look to decide whether my work is good enough (in which case: close this issue), or whether it should be improved (in which case: work on the corresponding repo)