Update grid to match new guidelines

[Studio384]

The grid still adheres to pre-0.19 icons. And more changes have been made since.

• Move the modifier icon space 1px to the left.
• Drop the left and right save zones.
• Make the base circle 16x16.
• Provide a seperately toggled circle to test for visual balance.

Note that the change to the base circle size also means that various icons will have to be updated to adhere to this new guideline.

[Studio384]

A new grid has been introduced with the following changes:

• Properly names all grid lines
• Increases the size of the circle helper line from 15x15 to 16x16
• Merges the outer border and inner crosshairs into a single shape
• Removes the modifier zone
• Drops the left and right save zones, reducing the grid to 16x16

Additionally, the grid itself is now a component. The icon grid is named Primary with a second option called Modifier to design the modifier icons.

The Modifier variant is essentially a reduced version of the Primary grid. With all sizes halved. The inner circle has been removed in this variant.