feat: Change favicon color from gray to blue (#3498db)

The gray favicon was invisible on light backgrounds. Changed all icons
to a visible blue color for better visibility across all themes.

Author: flemzord

.gitignore

@@ -24,7 +24,6 @@ upstream-patches
 app/views/home/404.*
 app/views/layouts/_footer.*
 app/assets/stylesheets/local/*
-public/favicon.ico
 
 # files added in production
 lib/tasks/deploy.rake