build: Bring SVGO optimization to build step

Enabling SVGO automation with 'grunt-svgmin' and conservative
plugin settings to build step, among those:
- enable removeRasterImages and sortAttrs,
- disable cleanupIDs, removeDesc, removeTitle, removeViewBox &
  removeXMLProcInst and
- make use of pretty, indent and multipass options.

Also updating SVG accordingly.

Bug: T185596
Change-Id: I0030a711a2947ca8c1eb4e56d8540661c72a2639

package.json

@@ -10,6 +10,7 @@
     "grunt-eslint": "20.1.0",
     "grunt-jsonlint": "1.1.0",
     "grunt-stylelint": "0.9.0",
+    "grunt-svgmin": "5.0.0",
     "stylelint": "8.2.0",
     "stylelint-config-wikimedia": "0.4.2"
   }