Change brand color and logotypes (#18592)

- Add rake task for generating Apple/Android icons and favicons from SVG
- Add rake task for generating PNG icons and logos for e-mails from SVG
- Remove obsolete Microsoft icons and configuration
- Remove PWA shortcut icons

app/javascript/styles/application.scss

@@ -6,6 +6,7 @@
 
 @import 'mastodon/reset';
 @import 'mastodon/basics';
+@import 'mastodon/branding';
 @import 'mastodon/containers';
 @import 'mastodon/lists';
 @import 'mastodon/footer';

app/javascript/styles/mastodon/about.scss

@@ -688,7 +688,7 @@ $small-breakpoint: 960px;
     align-items: center;
     padding: 50px;
 
-    svg {
+    .logo {
       fill: $primary-text-color;
       height: 52px;
     }

app/javascript/styles/mastodon/branding.scss

@@ -0,0 +1,3 @@
+.logo {
+  color: $primary-text-color;
+}

app/javascript/styles/mastodon/components.scss

@@ -2538,7 +2538,6 @@ a.account__display-name {
   padding: 40px;
 
   .logo {
-    fill: $primary-text-color;
     width: 50px;
     margin: 0 auto;
     margin-bottom: 40px;

app/javascript/styles/mastodon/containers.scss

@@ -20,8 +20,7 @@
     justify-content: center;
     align-items: center;
 
-    svg {
-      fill: $primary-text-color;
+    .logo {
       height: 42px;
       margin-right: 10px;
     }
@@ -320,7 +319,7 @@
       display: block;
       padding: 15px;
 
-      svg {
+      .logo {
         display: block;
         height: 18px;
         width: auto;

app/javascript/styles/mastodon/footer.scss

@@ -132,19 +132,19 @@
     }
 
     .brand {
-      svg {
+      .logo {
         display: block;
         height: 36px;
         width: auto;
         margin: 0 auto;
-        fill: lighten($ui-base-color, 34%);
+        color: lighten($ui-base-color, 34%);
       }
 
       &:hover,
       &:focus,
       &:active {
-        svg {
-          fill: lighten($ui-base-color, 38%);
+        .logo {
+          color: lighten($ui-base-color, 38%);
         }
       }
     }

app/javascript/styles/mastodon/variables.scss

@@ -12,7 +12,7 @@ $red-bookmark: $warning-red;
 $classic-base-color: #282c37;         // Midnight Express
 $classic-primary-color: #9baec8;      // Echo Blue
 $classic-secondary-color: #d9e1e8;    // Pattens Blue
-$classic-highlight-color: #2b90d9;    // Summer Sky
+$classic-highlight-color: #6364ff;    // Brand purple
 
 // Variables for defaults in UI
 $base-shadow-color: $black !default;