Constant/Lifetime components

## What problem does this solve or what need does it fill?

There are some components that don't make sense to change at all over the lifetime of the game, such as the name of an item.

It might make sense to disallow removing such components

## What solution would you like?

```rust
#[derive(Component)]
#[component(constant)]
pub struct ItemName(String);

// Throws a compiler error
commands.entity(entity).remove::();
```

I have no idea how, or even if this would work, this is mostly just a random thought I had.

## What alternative(s) have you considered?

Same as before, but keep in mind you shouldn't be changing them.

Start by reviewing the `#[derive(Component)]` and `#[component(constant)]` entry points, along with `commands.entity(entity).remove::()`. Determine whether constant components and compile-time removal prevention are feasible, then seek an agreed design. Done means the behavior and implementation scope are decided, with the requested restriction covered by tests.

Written by the indexing model from the issue text.