Update Cozystack logo and favicons to the new brand mark

Replace the navigation logo and the full favicon set with the refreshed
Cozystack brand mark (new icon + "COZYSTACK" wordmark).

  - assets/icons/logo.svg            new horizontal wordmark (white, for dark nav)
  - static/favicons/*                regenerated from the new icon

The nav logo is tightly cropped (no surrounding padding) and the navbar
logo height is bumped 30px -> 36px so the new icon + wordmark reads at a
comparable size to the previous logo.

Favicons use the new icon glyph on a #1a1a1a square (matching the site's
existing theme color) and keep the same file names and pixel dimensions
as before. SVGs are optimized via autocrop.cncf.io.

Signed-off-by: Viktoriia Kvapil <bisunviktoria@gmail.com>

Author: Viktoriia Kvapil

assets/icons/logo.svg

@@ -37,7 +37,7 @@ nav.navbar {
     svg {
       display: inline-block;
       margin: 0 10px 0 -6px;
-      height: 30px;
+      height: 36px;
       @include media-breakpoint-up(lg) {
         margin: 0 10px;
       }