add code for website tracking

[amaiaita]

Description

❓What:

🧠Why?:

👨‍💻How?:

Checklist:

Have checked for the following:

• The website still builds correctly, and you can view it using mkdocs serve.
• There are no new "warnings" from mkdocs (see here for existing warnings you can safely ignore)
• Does your page follow the page template (or here in Markdown)? (need to make a new one specific to NHSE Data Science)
• Spelling errors
• Consistent capitalization
• Consistent numbers
• Material features incorrectly implemented: search for code blocks and markers (e.g. !!!).
• Code snippets don't work
• Images not working
• Links not working

Where it was tested

• Github Codespaces - 2-core, 4GB RAM, 32GB hard drive
• devcontainer.json describes further settings

Existing Warnings

The following are errors that are already existing in the mkdocs build and that you can safely ignore when creating a PR:

INFO    -  The following pages exist in the docs directory, but are not included in the "nav" configuration:
             - what_is_data_science/index.md
             - what_is_data_science/Benefits of Data Science in the NHS.md
             - what_is_data_science/How you can learn Data Science.md