Show multiple last values for all eligible Overlays, not just Building overlay

[mnalis]

Introduction

Regarding caching recent answers, there are several "types" of overlays:

1. Street lighting, Surfaces - simple single answer based overlay, currently remembers only 1 recent answer
2. Buildings - also, simple single answer based overlay, currently remembers multiple (one row) recent answers
3. Places, Things - have advanced multiple recent answers UI (as it needs to show not just picture but also text description, so eats up whole screen)
4. Sidewalks, Bike paths, Street parking - have more complex orientation dependent UI (with 1 recent answer cache)
5. Addresses - does not make sense to have "recent answers" (it needs incremental answers, which are provided by its separate highly-efficient UI).

(Inspired by #5539 (comment))

Use case

"1 recent answer cache" helped in lot of cases when it was introduced! However, surprisingly often, answers alternate between last 2 (or even 3 or 4!) values for type 1 above (Surfaces & Street lighting overlays).

For example, dirt surface becomes grass (or compacted) on paths, or asphalt switches to paving_stones and then back to asphalt in cities (esp. on crossings), or lit / not lit changes depending on main street / side alleys while one walks.

In all those cases, "1 recent answer" does not help at all, and user has to do full selection (including scrolling and searching), which wastes clicks and time, and is mentally taxing and not fun.

Proposed Solution

I would like for Street lighting and Surfaces overlays to also have multiple (one row) of recent answers, just like Buildings overlay does. That would:

• fix the described use case, reducing the number of clicks and searching/scrolling through the list when user needs to select that other recently used value
• reduce number of different Overlay UIs for "recent answers" (by converting type 1 from introduction to type 2).