[Compile] Module importing and loading system

[anistark]

Implement Python's import system for WebAssembly.

Scope:

• Module loading (import module)
• From imports (from module import item)
• Package imports (import package.module)
• Module search path and resolution

Acceptance Criteria:

• import math loads math module
• from json import dumps works
• Relative imports work
• Module caching works