Maps as a full-fledged record type

This is an idea that's been bouncing around in my head for a while, and with #2363393: Make "Area" into a type of Farm Asset → on our mind in the context of #3092830: [META] farmOS 2.x Roadmap → - it could be worth exploring soon...

Imagine instead of "Areas / Assets / Logs" in the main menu (because Areas will most likely become Asset type(s)), we have: "Maps / Assets / Logs".

The "Maps" menu item would lead to a page that allows you to create any number of "Maps" for your farm. These maps would be entities that could reference specific assets (and show their geometries), as well as raw geometry data that is specific to the Map.

This would allow you to create different maps for different purposes, including different sets of assets/geometries. We could potentially also link these Maps to Plans - such that any time you create a Crop Plan (for example) it creates an associated Map for that Plan, and automatically adds Plantings to it.

The main idea is: it's valuable to create "Maps" of your farm. Right now farmOS provides some basic maps by default (eg: the "All areas" map and the "Asset cluster" maps). But it would be great to open that up and allow users to make their own maps - which can include any number of specific assets, as well as just plain old geometries that don't exist anywhere but the map itself.

Use-cases:

- Planning / mocking up possibilities
- Mapping fencelines or irrigation sources without having to create assets for them
- Making the process of initial farm mapping easier (see #2679108: Multi-area editor → )

Some of my chat with Paul today, with some other ideas, for posterity:

mstenta: "Maps" would not be an asset type... but would be configurable collections of things that should be shown in a map
mstenta: So you could have different maps for different purposes
mstenta: With a mix of actual assets, and just raw geometries
mstenta: (maybe it could be an asset type, I suppose... but that's neither here nor there... an entity type of some sort)
paul121: I really like that idea
mstenta: I was thinking: the main menu could then become: Maps / Assets / Logs / Plans
mstenta: instead of Areas
paul121: almost like different "views"
mstenta: yea exactly
mstenta: that would be great for permaculture planning
paul121: the Planting page would have a default view that includes all Plantings
mstenta: you could sketch up a map that is completely disconnected from everything else that's going on in the system
mstenta: and then add real assets to it later
mstenta: eg: "Add a map" > "Name: Tree planting ideas" > sketch away
mstenta: And maybe the map could be used to generate assets
mstenta: eg: draw out all your fields and buildings on the map, then select one and click "Create Land Asset" or "Create Structure Asset"
mstenta: Could be the "multi area editor" we've talked about ( #2679108: Multi-area editor → )
paul121: very cool
paul121: That helps solve the "show any asset's geometries on the map"
paul121: so a Plant doesn't have to be located in an area
mstenta: yes!
mstenta: it can just have a geometry
mstenta: that fits with my current thinking for v2 of the "movement" logic (which is another whole topic haha) ( #2991383: Migrate movement fields from Field Collection to Log → )