HLD brainstorming - Formatted text table columns

[jattasNI]

Pull Request

🤨 Rationale

First pass of design document for #1011. I'm considering formatted text more holistically, so this is also relevant to #1014.

👩‍💻 Implementation

The document describes several alternative high-level approaches and proposes which ones we should pursue. Once we agree on the high-level direction in this PR, I will move it back to draft while I refine the proposed APIs and fill in the rest of the HLD template.

[atmgrifter00]

I think the possible proposed solution outlined in the "Client specifies formatting function" section is at odds with what an app developer would expect for an API, in that they would be expected to create a custom column implementation. The first variant, I think, is what clients typically expect, and resembles what Ag-grid provides.

[jattasNI]

I'll leave this open since I haven't addressed it (it's one level more detailed than I'm seeking agreement on at this moment, though still a good discussion to have).

I like the proposed approach of deriving from an abstract element class to define a new column type because it makes it easy to associate the formatting function with the column definition in JS code (they're in the same class). The approach of setting a formatting function via a property on the column element requires you to get a reference to the column in JS/TS/C# code which seemed more annoying to me (especially in Blazor).

[atmgrifter00]

One thing that may be worth considering is if we do have a nimble-table-column-number that exposes an API for formatting the value, whether or not that API should be reflected in the number-field component (and what the implications of that are).

[jattasNI]

Closing in favor of #1224. All of the excellent feedback in this PR has been captured in that update.