DOCS: Better documentation for climate indicators and indices

[SarahG-579462]

Addressing a Problem?

The current documentation for climate indicators (https://xclim.readthedocs.io/en/latest/indicators.html) is very hard to read: lines extend indefinitely, all indicators are on the same page, and details about the calculations and inputs require jumping between multiple places in the documentation. Some indicators have extra parameters (e.g. id) that others don't. The realm for "atmos" is very large, making searching for the correct indicator quite laborious.

The documentation on the difference between indices and indicators isn't located in an easily accessible location, currently it's in "examples > extending xclim > indices vs indicators". There is some description on the pages themselves for indicators/indices, but it does not link to this page.

The indices module does not distinguish realms, making searching laborious (e.g., 599 results for "temperature"...)

Potential Solution

• Move the discussion of indicator vs index to a more accessible location, and link to it on both pages for indicators and indices. #1436
• Move the API for climate indicators into the climate indicators page, to make reading the api page easier. #1437
• Explain why some indicators don't have an id, or other parameters.
• More clearly indicate the requirements for calculating indicators and indices #1438
• potentially have a link from these to atmos in the atmos/__init__.py, as from xc.core.indicators.atmos.temperature import *, for example
• Create subrealms/categories, atmos.temperature, atmos.precipitation, atmos.wind, atmos.mixed, etc, for temperature, precip, wind and mixed indicators #1433

Additional context

No response

Contribution

• I would be willing/able to open a Pull Request to contribute this feature.

Code of Conduct

• I agree to follow this project's Code of Conduct

[Zeitsperre]

Related issue: #1312

[Zeitsperre]

@SarahG-579462

potentially have a link from these to atmos in the atmos/init.py, as from xc.core.indicators.atmos.temperature import *, for example

I feel like we already do this, no?