Wrapper validation

[nerfZael]

Implemented the package-validation package that can be used to validate wasm packages.
Main class that accomplishes this is the WasmPackageValidator:

class WasmPackageValidator {
  constructor(private constraints: WasmPackageConstraints) {}
  async validate(reader: PackageReader): Promise<ValidationResult> ;
 }

The validator takes in WasmPackageConstraints which define the constraints that the wrapper needs to follow in order to be considered valid.

type WasmPackageConstraints = {
  maxSize: number;
  maxFileSize: number;
  maxModuleSize: number;
  maxNumberOfFiles: number;
};

The validate method can be called to validate a wasm package that can be read through the PackageReader that was passed as the argument:

interface PackageReader {
  readFileAsString: (path: string) => Promise<string>;
  readFile: (path: string) => Promise<Buffer>;
  exists: (path: string) => Promise<boolean>;
  getStats: (path: string) => Promise<PathStats>;
  readDir: (path: string) => Promise<string[]>;
}

Closes: #803