Move Variants into the Components folder

Continue grouping the standalone modules under Components. Updates the
nightly.yml include path and the app icon banner path used by the
configure-nightly CI command.

Components/Variants/Nightly/nightly.yml

@@ -0,0 +1,12 @@
+settings:
+  APP_GROUP_IDENTIFIER: group.io.element.nightly
+  BASE_BUNDLE_IDENTIFIER: io.element.elementx.nightly
+  IS_NIGHTLY_BUILD: true
+
+targets:
+  ElementX:
+    settings:
+      base:
+        ASSETCATALOG_COMPILER_APPICON_NAME: NightlyAppIcon
+    sources:
+    - path: Resources