Add icon-compare to openproject font

This adds `icon-compare` from the updated OpenProject font.

[ci skip]

app/assets/fonts/openproject_icon/openproject-icon-font.svg

@@ -274,4 +274,5 @@
 <glyph unicode="&#57606;" d="M256 457l177-307-354 0z m-177-356l354 0 0-46-354 0z"/>
 <glyph unicode="&#57605;" d="M256 55l-177 307 354 0z m-177 402l354 0 0-46-354 0z"/>
 <glyph unicode="&#57607;" d="M46 259l210 210 210-210-210-209z"/>
+<glyph unicode="&#57608;" d="M177 326l158 0 0-24-158 0z m0-190l158 0 0-25-158 0z m70 258l25 0 0-159-25 0z m-181 118l32 0 0-512-32 0z m348-118l32 0 0-394-32 0z m-334-361l345 0 0-33-345 0z m0 479l238 0 0-33-238 0z m240 7l126-125-24-24-126 126z"/>
 </font></defs></svg>

app/assets/stylesheets/fonts/_openproject_icon_font.lsg

@@ -65,6 +65,7 @@
 <li><span class="icon-column-left"></span> column-left</li>
 <li><span class="icon-column-right"></span> column-right</li>
 <li><span class="icon-columns"></span> columns</li>
+<li><span class="icon-compare"></span> compare</li>
 <li><span class="icon-console"></span> console</li>
 <li><span class="icon-contacts"></span> contacts</li>
 <li><span class="icon-copy"></span> copy</li>

app/assets/stylesheets/fonts/_openproject_icon_font.sass

@@ -1001,6 +1001,9 @@ dt > .icon-wiki-page:before,
 .icon-milestone:before
   content: "\e107"
 
+.icon-compare:before
+  content: "\e108"
+
 /* remove once all menu items have an icon */
 .no-icon
   margin-left: 15px