Add icons at missing sizes, clean up SVG metadata

Adds app icon at 64px, 96px. This should give a cleaner look in system menus like App Finder, Whisker Menu.

Removes some leftover/draft content in SVGs.

Removes export path strings from SVGs, metadata which Inkscape added on export.

Note: Inkscape has recently changed how export paths are saved, using relative paths, so that shouldn't be an issue in the future.