Pause Menu and basic options list

Make a pause menu that pauses the game when you press esc. Make an options button, a save button, and an exit to main menu button. pressing escape again should unpause the game, and there should also be a little button in the top right of the pause menu you can click to resume the game as well.

- Stepan will add functionality to the save button once you are done. Make sure the rest of the buttons work.
- The exit to main menu button should bring you to the main menu.
- The options menu should open an options menu that lets you change keybinds for movement, opening inventory, opening skill tree, opening NPC /Teleport menu.