GUI: Various refinements

[waydabber]

The GUI should receive some minor refinements. Nothing groundbreaking, just some tweaks here and there.

• Header chevrons actually serve no real purpose and are not needed
• Alignment of the right side of the menu is not perfect everywhere
• Some header text letters do not fit perfectly their frame, this needs some adjustments
• Header items are not sized/lined up consistently
• Some icons need replacing
• Tools icon looks out of place
• Header icons could be rendered hierarchical instead on Ventura
• Gap between itemless blocks must be eliminated
• Slider inline fonts should be a bit smaller, resolution % and value should keep a bit more distance with a divisor between
• Header heights should be a bit expanded to make the menu feel less claustrophobic
• Generally the rendering should be a bit lighter/airier especially in light mode.
• Remove bottom menu shine embellishment to provide a cleaner/flatter look