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/helpers/accounts_helper.rb

@@ -23,20 +23,20 @@ module AccountsHelper
     if user_signed_in?
       if account.id == current_user.account_id
         link_to settings_profile_url, class: 'button logo-button' do
-          safe_join([svg_logo, t('settings.edit_profile')])
+          safe_join([logo_as_symbol, t('settings.edit_profile')])
         end
       elsif current_account.following?(account) || current_account.requested?(account)
         link_to account_unfollow_path(account), class: 'button logo-button button--destructive', data: { method: :post } do
-          safe_join([svg_logo, t('accounts.unfollow')])
+          safe_join([logo_as_symbol, t('accounts.unfollow')])
         end
       elsif !(account.memorial? || account.moved?)
         link_to account_follow_path(account), class: "button logo-button#{account.blocking?(current_account) ? ' disabled' : ''}", data: { method: :post } do
-          safe_join([svg_logo, t('accounts.follow')])
+          safe_join([logo_as_symbol, t('accounts.follow')])
         end
       end
     elsif !(account.memorial? || account.moved?)
       link_to account_remote_follow_path(account), class: 'button logo-button modal-button', target: '_new' do
-        safe_join([svg_logo, t('accounts.follow')])
+        safe_join([logo_as_symbol, t('accounts.follow')])
       end
     end
   end
@@ -99,12 +99,4 @@ module AccountsHelper
 
     [prepend_str, account.note].join(' · ')
   end
-
-  def svg_logo
-    content_tag(:svg, tag(:use, 'xlink:href' => '#mastodon-svg-logo'), 'viewBox' => '0 0 216.4144 232.00976')
-  end
-
-  def svg_logo_full
-    content_tag(:svg, tag(:use, 'xlink:href' => '#mastodon-svg-logo-full'), 'viewBox' => '0 0 713.35878 175.8678')
-  end
 end