Docs: include a 'How do I...?' table to direct on common tasks

[sadielbartholomew]

As part of our summit this week, we have identified that users would benefit from a page in the documentation which centers around a table which list common tasks that a user might want to do and maps them to relevant methods and their API reference pages; examples; and documentation sections.

A great example of this is an equivalent table in the xarray docs. As well as pointing to methods of direct relevance as per that table, we can include some extra columns which point to relevant sections of the Tutorial and relevant recipes, where applicable.