Use custom typer types for times/format/sdtype/subtype

[rec]

https://typer.tiangolo.com/tutorial/parameter-types/custom-types/

Since we're doing four of these, might as well look into custom click types too.

[rec]

This went well and I'm going to add two more

• assignment: name=value
• alias: name=value or just name

That covers aliases well, and metadata so-so