Add documentation on icon theming (closes #233)

admin_manual/configuration_server/theming.rst

@@ -18,3 +18,15 @@ In the administrative settings you can modify the appearance of Nextcloud:
 Log in page   
 
 .. figure:: ../configuration_server/images/theming-log-in-page.png
+
+Theming of icons
+================
+
+Nextcloud will automatically generate favicons and home screen icons
+depending on the current app and theming color. 
+
+This requires the following additional dependencies:
+
+ - PHP module imagick
+ - SVG support for imagick (e.g. `libmagickcore5-extra`)
+

admin_manual/operations/theming.rst

@@ -6,4 +6,7 @@ Theming Nextcloud
     :maxdepth: 2
     :hidden:
 
-The theming is documented in the `developers documentation <../../developer_manual/core/theming.html>`_.
+
+Theming can be done very easily using the shipped `theming app <../configuration_server/theming.html>`_, which is enabled by default.
+
+For more individual theming options please head over to the `developers documentation <../../developer_manual/core/theming.html>`_.

developer_manual/app/theming.rst

@@ -34,3 +34,9 @@ The following information is available:
 * **OCA.Theming.slogan** Instance slogan
 * **OCA.Theming.url**  Instance web address
 
+Icons
+=====
+
+The theming app will automatically generate favicons and home screen icons for
+each app by using the icon `img/app.svg` inside of the app folder. Any custom
+favicon set by an app will only be visible when the theming app is disabled.