Lucien Bill

Results 3 issues of Lucien Bill

This changes enables to use [counter.dev](https://counter.dev/) for analytics simply by filling the username in the `counter_dev` in the config.yml file.

Just a few words that specify that building the site takes time (related to issue #1898)

Hi! I discovered counter.dev recently and I love it. In this PR : - [x] code for counter.dev tracking - [x] unit tests - [x] updated REAMDE.md