App Icon updates for 3.36

There are a few core app icons I'd like to improve for 3.36, in particular:

• Web -- The mirrored cursor is bad
• Software -- The whole thing feels too flat and the perspective doesn't work
• Notes -- It's a yellow blob
• Calculator -- It's not a physical object and the shape is boring
• Calendar -- The square with a number in it looks bad/boring
• 2048
• Image Viewer -- The gradient is meh (my fault :D)
• Cheese -- The smile is confusing and a bit creepy, and the colors don't look that great. I'd like to try a generic photobooth icon (and then we can also rename it to Photo Booth)
• Music -- After seeing the nightly icon with the lighter gray I feel like we should maybe do that in the regular one too
• Help -- Rendering glitch -- ghosting.

Followup from https://gitlab.gnome.org/Teams/Design/icon-revolution/issues/2