Improve Sphinx docs

[ValueRaider]

Reorganise new documentation, add some missing content.

@ericpien can you sanity-check this? The changes are mostly AI - lots of warnings but seems to work, not sure how the Action will cope.

[paulmcq]

in doc/source/advanced/caching.rst line 48, suggest being a little less terse:
To reduce the number of requests to Yahoo servers, yfinance caches some data locally: timezones to localize dates, and the cookie & crumb. The cache location depends on the OS:

[ericpien]

hey @ValueRaider I noticed this was converted to draft. Should I still review as is?

I see the vision in 1. Splitting out Ticker to underlying functions and 2. Changing the class.rst template but the implementation will take some work to rid of the warnings and unnecessary methods like __dict__ and duplicate __init__.

[ValueRaider]

I misuse draft state - we really need another state to mean ready for review but probably not merge.

All warnings fixed.