Update watch face: modular refactor + OWM/Solar/background + codegen tools

- Split render into FieldTable/Fields/Icons/Layout/Settings modules
- Add Fenix8V3Background, Owm (weather), Solar modules
- Add tools/ generators (gen_fields/gen_icons/gen_themes/gen_preview_svg)
- Tune README/manifest/strings/settings

manifest.xml

@@ -38,6 +38,8 @@
              requested, so altitude and pressure come from Activity.Info instead. -->
         <iq:permissions>
             <iq:uses-permission id="UserProfile"/>
+            <iq:uses-permission id="Communications"/>
+            <iq:uses-permission id="Background"/>
             <iq:uses-permission id="SensorHistory"/>
         </iq:permissions>