Added support for TypeScript when 'jss build'ing

[boro2g]

I've not added in

config.module.rules.push({
    test: /\.(ts|tsx)?$/,
    loader: 'ts-loader',
    exclude: /node_modules/,
    options: {
      appendTsSuffixTo: [/\.vue$/],
    }
  });

as I figured people probably wanted to opt into that.

If adding ^ we'd need to update package.json / package-lock.json with ts-loader and typescript and also add to webpack override: config.resolve.extensions.push('.ts');

[sc-dawidrutkowski]

@boro2g I've merged your pull request.