Online doc pages should have analytics

[szhorvat]

The online doc pages at https://python.igraph.org/ should have Google Analytics, and hooked up to the igraph Google Analytics account.

@iosonofabio, is this reasonably easy to do in such a way that analytics are only included on the website, but not in any other situations when the docs are built (e.g. for Dash, offline distribution, etc.)?

Reasoning: Relevance for grant applications. Otherwise I am not too keen on web analytics.

[ntamas]

You can add a Google Analytics tracking code to the project on the Readthedocs admin area and then the online docs are generated in a way that this tracking code is added. As far as I know it won't affect docs that we generate from the command line as they do not have access to the admin area of the Readthedocs site. So this should be okay.

In fact, we already have a GA tracking code in place, but I don't know where the data is going to -- I don't see it on my GA account. I can create a new GA property with a different tracking code if you want to and then we can start using that.