Added vuex module for setting if darkmode is supported in users browser

src/modules/darkmodeModule.js

@@ -0,0 +1,23 @@
+export default {
+  namespaced: true,
+  state: {
+    darkmodeSupported: undefined,
+    userChoice: undefined
+  },
+  getters: {
+    darkmodeSupported: (state) => {
+      return state.darkmodeSupported
+    }
+  },
+  mutations: {
+    SET_DARKMODE_SUPPORT: (state, browserSupported) => {
+      state.darkmodeSupported = browserSupported
+    }
+  },
+  actions: {
+    findAndSetDarkmodeSupported({ commit }) {
+      const browserSupported = window.matchMedia('(prefers-color-scheme)').media !== 'not all'
+      commit('SET_DARKMODE_SUPPORT', browserSupported)
+    }
+  }
+}