Huge code cleanup, Architectury & Watermedia

- A huge cleanup of the codebase
- Make use of the Architectury build system
- Replaced VideoLib with WATERMeDIA (More features, better stability, multiplatform support)

common/src/main/resources/picturesign.mixins.json

@@ -0,0 +1,14 @@
+{
+  "required": true,
+  "package": "eu.midnightdust.picturesign.mixin",
+  "compatibilityLevel": "JAVA_17",
+  "client": [
+    "MixinSignBlockEntityRenderer",
+    "MixinHangingSignBlockEntityRenderer",
+    "MixinSignEditScreen",
+    "MixinSignBlockEntity"
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  }
+}