Sopel-lichess

You know, the anchor, the thing after the thing that is used for hash-tag and stuff. Yeah, those... I forgot about them, so here is a fix to make sure these are identical:

* `https://lichess.org/4dnClfgu/black`
* `https://lichess.org/4dnClfgu/black#5`

Better, right? Right.

Lichess can point to the same game with different URLs:

* `https://lichess.org/4dnClfgu`
* `https://lichess.org/4dnClfgu/black`
* `https://lichess.org/4dnClfgu/white`

When there is a suffix (either black or white), the plugin will format the player's name of that color in bold.

Also fixed a bug with a trailing slash.

Initial release of sopel-lichess:

* handle game URLs
* handle TV channel URLs
* handle player URLs

This requires a lichess.org API key.