Expanding the button shine logic

[zenseii]

Preliminary checks

• I've checked that there aren't other open issues on the same topic.

Describe the problem requiring a solution

The current button shine logic for engine generated buttons is very bare-bones and therefore repetitive and easy to tell apart from the original buttons' shine effect.

Requirements:
The effect needs to be present on the sides and bottom side of buttons too for buttons that are big enough. Also the shine effect shouldn't be exactly the same for every button to keep variety as seen on original buttons.

Describe the possible solution

Expand the function by:

1. Check the width and height of the button and from this determine if a button should have the effect on the sides and the bottom part and how many shines. The distinction will be between single lined text buttons and multilined ones.
2. To make the shine different between buttons of the same size, we can look at the button string value and make this value determine where and how many shines are added to the button. This makes the effect consistent for the same text and between loads of the engine.

Additional info

Different types of shines might have to be added as images or functions that can be copied, or generated on the fly.