add settings GUI

[Rudxain]

Provide users a way to input their customization preferences, and use localStorage for persistence.
These settings would include:

• Speed
• Colors
• Character set
• Size
• Dimming factor
• Resizing delay (for debouncing)
• Play & pause functionality

[Rudxain]

This will be the most important update from a user's POV.
I still need to learn how to make a dialog box with good UX, and decide how the dialog should be triggered to be shown

[Rudxain]

The settings will be contained within a general-purpose div menu. The menu will be centered at the bottom of the viewport, for phone users.

When reloading the page, a button hint should get animated, then disappear after some seconds. If the user clicks the button (at any time) it'll display the overlay menu