Added a language selection option on index.html

[gyuhyeon]

simply adds a select field to pass response in the form.

[jjangsangy]

Good stuff, so here are the features that I would like to get implemented before merging this PR.

Requirements

• [ ] Error page when user submits input that doesn't match the page content.
• [ ] Cleanup the styling on the search bar.
  • You can decide how much you want to consider this. If you're confident language detection is possible, it'll just go back to 2 inputs.

Optional Features

• [ ] Implement Language Detection
• [ ] Figure out what fidelity you can do language detection. Are there other simpler options?