[ Pending RFC ] create Cell

[NullVoxPopuli]

I want to RFC Resources, but we don't really have an implemented way to have reactivity in them right now.

We have:

• trackedData in @glimmer/validator -- this whole package should not be used by ember users tho, and most of its exports are not-RFC'd and should be considered private API
• @glimmer/tracking/primitives/storage -- this would work as an implementation of "Cell", but isn't implemented yet
• @tracked - requires creating class state, which many would feel is too cumbersome / verbose when for the "simple" cases, like having one value

Tho, now that I've implemented this, I wonder if it can be placed in @glimmer/tracking, since @glimmer/validator exports so much.

[github-actions]

	Dev	Prod
This PR	676K └─┬ . 191K ├── runtime 162K ├── syntax 124K ├── compiler 81K ├── opcode-compiler 49K ├── manager 19K ├── validator 11K ├── program 9.0K ├── reference 7.0K ├── destroyable 6.1K ├── util 4.2K ├── node 3.8K ├── global-context 2.6K ├── wire-format 1.0K ├── vm 966B ├── encoder 844B ├── vm-babel-plugins 565B └── owner	262K └─┬ . 71K ├── runtime 69K ├── syntax 56K ├── compiler 26K ├── opcode-compiler 15K ├── manager 5.0K ├── program 4.4K ├── validator 3.7K ├── reference 2.4K ├── util 2.1K ├── node 1.6K ├── wire-format 1.5K ├── destroyable 737B ├── vm 563B ├── global-context 511B ├── encoder 469B ├── vm-babel-plugins 155B └── owner
Main	676K └─┬ . 191K ├── runtime 162K ├── syntax 124K ├── compiler 81K ├── opcode-compiler 49K ├── manager 19K ├── validator 11K ├── program 9.0K ├── reference 7.0K ├── destroyable 6.1K ├── util 4.2K ├── node 3.8K ├── global-context 2.6K ├── wire-format 1.0K ├── vm 966B ├── encoder 844B ├── vm-babel-plugins 565B └── owner	262K └─┬ . 71K ├── runtime 69K ├── syntax 56K ├── compiler 26K ├── opcode-compiler 15K ├── manager 5.0K ├── program 4.1K ├── validator 3.7K ├── reference 2.4K ├── util 2.1K ├── node 1.6K ├── wire-format 1.5K ├── destroyable 737B ├── vm 563B ├── global-context 511B ├── encoder 469B ├── vm-babel-plugins 155B └── owner