Contribute to upstream Docsify Matomo plugin

[egpbos]

Following #421, we are now using a custom version of the Matomo plugin for Docsify. We should:

1. make a PR with Docsify to modify their version of the Matomo plugin to add the features and fixes we need
2. after that, use the original Docsify Matomo plugin and remove our custom version from the Guide.