gnu: Add ungoogled-chromium.

* gnu/packages/aux-files/chromium/master-preferences.json,
gnu/packages/chromium.scm: New files.
* gnu/local.mk (GNU_SYSTEM_MODULES): Adjust accordingly.

gnu/local.mk

@@ -100,6 +100,7 @@ GNU_SYSTEM_MODULES =				\
   %D%/packages/check.scm			\
   %D%/packages/chemistry.scm			\
   %D%/packages/chez.scm				\
+  %D%/packages/chromium.scm			\
   %D%/packages/ci.scm				\
   %D%/packages/cinnamon.scm			\
   %D%/packages/clojure.scm			\

gnu/packages/aux-files/chromium/master-preferences.json

+{
+    "distribution": {
+        "import_bookmarks": false,
+        "make_chrome_default": false,
+        "make_chrome_default_for_user": false,
+        "verbose_logging": true,
+        "skip_first_run_ui": true,
+        "suppress_first_run_default_browser_prompt": true
+    },
+    "browser": {
+        "has_seen_welcome_page" : true,
+        "check_default_browser" : false
+    },
+    "dns_prefetching": {
+        "enabled": false
+    },
+    "alternate_error_pages": {
+        "enabled": false
+    },
+    "hardware": {
+        "audio_capture_enabled": false
+    },
+    "default_apps": "noinstall",
+    "hide_web_store_icon": true,
+    "homepage": "https://www.gnu.org/software/guix/"
+}