docs: added a timers page, added a note in setting_status for timers

[Jaskowicz1]

This PR adds a page for timers, showing people how to use timers along with making them one-shot too.

Documentation change checklist

• [x] My documentation changes follow the docs style guide and any code examples follow the coding style guide.
• [x] I tested that my change works before raising the PR (via running doxygen, and testing examples).
• [x] I have not moved any existing pages or changed any existing URLs without strong justification as to why.
• [x] I have not generated content using AI or a desktop utility such as grammarly.

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