Glob import syntax for require-by-string

Motivation

Many patterns utilize current dynamic requires, or load in luau files manually:
- ECS systems
- The "service" pattern
- Module initializers
- Tests
The alternative (writing out manual requires) is quite cumbersome and not feasible to expect developers to do
Cross-runtime/platform automated testing is currently impossible
Current dynamic requires are not type safe and can have cyclical dependency errors which are not picked up on. This isn't a conceptual limitation, it is totally possible to report.
Cross-module compilation may be wanted in the eventual future. But this pattern is common and will not be going away. There should be a way to express "requiring all children of a directory" while still having full cross-module compilation.

local children = require("directory/*)") -- array
local descendants = require("directory/**") -- array

Provide a dictionary where { [name]: return value }?
- In descendants, this might cause duplicates.
- Include file extension? Can have duplicates if no file extension.