CSET full capability example linked to documentation

When we produce a new CSET release, we should provide a website showing the full set of diagnostics/capability as a 'cookbook', or library, to showcase its functionality. This could be using public Met Office data. This could also be useful for demo's of CSET, having a standard dataset that can produce all the plots.

Start by reviewing the CSET documentation and existing diagnostic or capability examples, then identify the scope of the proposed cookbook and the public Met Office dataset it would use. Before implementation, clarify which diagnostics and plots must be covered and what release-ready documentation or website constitutes done.

Written by the indexing model from the issue text.