luci-theme-openwrt-2020: fix logo.svg according to Logo Usage Guidelines

The "White & Dark Blue" logo should have a background filled with PANTONE 306 C HEX #00B5E2.
SVG doesn't support background-color properly so use a rectangle instead.
The dark blue circle must be PANTONE 7463 C HEX #002B49

See https://openwrt.org/_media/docs/guide-graphic-designer/openwrt-logo-usage-guidelines.pdf

Signed-off-by: Sergey Ponomarev <stokito@gmail.com>

themes/luci-theme-openwrt-2020/htdocs/luci-static/openwrt2020/logo.svg

@@ -1,7 +1,8 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 81 98">
+  <path d="m 0 0 h 81 v 98 h -81 z" fill="#00B5E2"/>
   <path d="m 40.5,50.8 a 6.6,6.6 0 1 0 0,13.2 6.6,6.6 0 0 0 0,-13.2 m -40.5,-33.9 7,6.8 a 47.5,47.5 0 0 1 67.2,0 l 7,-6.8 a 57.2,57.2 0 0 0 -81.2,0" style="fill:#fff" />
   <path d="m 12.5,29.2 6.8,7 a 30,30 0 0 1 42.6,0 l 6.8,-7 a 39.7,39.7 0 0 0 -56.3,0" style="fill:#fff" />
   <path d="m 24.8,41.6 6.8,6.9 a 12.6,12.6 0 0 1 18,0 l 6.8,-6.9 a 22.3,22.3 0 0 0 -31.6,0" style="fill:#fff" />
-  <path d="m 64.9,39.7 a 30.2,30.2 0 1 1 -48.7,0 l -6.9,-7 a 39.9,39.9 0 1 0 62.5,0 z" style="fill:#072342" />
+  <path d="m 64.9,39.7 a 30.2,30.2 0 1 1 -48.7,0 l -6.9,-7 a 39.9,39.9 0 1 0 62.5,0 z" style="fill:#002B49" />
 </svg>