resources/images: Optimize all SVGs (partially by hand)

Passed with svgo 0.4.2 <https://github.com/svg/svgo>, then prepended
'<?xml version="1.0" encoding="UTF-8"?>' prolog to each file since
svgo sees it fit to remove it and that breaks file type detection.
svgo truncated all numerical values to a maximum of 3 decimal places
of precision.

Applied some additional optimizations by hand (with a text editor or
in Inkscape).

Did not touch upstream-managed SVG files, will submit separate
patches for them.

File size changes:

* cog-sprite.svg:    2,520 → 1,253 bytes – 50.3% smaller
* cog.svg:          17,961 → 1,154 bytes – 93.6% smaller
* display.svg:       2,591 → 1,053 bytes – 59.4% smaller
* help.svg:          1,790 →   674 bytes – 62.3% smaller
* input.svg:         5,515 → 2,092 bytes – 62.1% smaller
* remove-input.svg:  5,956 → 2,208 bytes – 62.9% smaller

Total:              36,333 → 8,434 bytes – 76.8% smaller

Details:

* cog-sprite.svg:
  * Use <defs> and <use> instead of duplicating the path data.

* cog.svg:
  * Vacuumed defs with Inkscape, there were weird leftovers there.

* input.svg:
  * Simplified the shapes.

* remove-input.svg:
  * As above. Reused the same path data with a transform to improve
    compression when embedded.

Bug: 56292
Change-Id: Iad1771829ba2711e4827befc1c73e34453734640
Merge "resources/images: Optimize all SVGs (partially by hand)"