add farm theme

src/themes/farm.ts

@@ -0,0 +1,19 @@
+import { Theme } from "./Theme";
+
+export const farmTheme: Theme = {
+  size: 32,
+  mine: () => import("../assets/themes/farm/mine.png"),
+  tile: () => import("../assets/themes/farm/tile.png"),
+  revealed: () => import("../assets/themes/farm/revealed.png"),
+  flag: () => import("../assets/themes/farm/flag.png"),
+  questionMark: () => import("../assets/themes/farm/question-mark.png"),
+  lastPos: () => import("../assets/themes/farm/last-pos.png"),
+  1: () => import("../assets/themes/farm/1.png"),
+  2: () => import("../assets/themes/farm/2.png"),
+  3: () => import("../assets/themes/farm/3.png"),
+  4: () => import("../assets/themes/farm/4.png"),
+  5: () => import("../assets/themes/farm/5.png"),
+  6: () => import("../assets/themes/farm/6.png"),
+  7: () => import("../assets/themes/farm/7.png"),
+  8: () => import("../assets/themes/farm/8.png"),
+};