Fix a couple of packaging issues

- Fix client classes not being included in Forge.
 - Only remap Nettty's HTTP classes, not all of them. This feels a
   little more error prone - maybe we should jar-in-jar this in the
   future.
 - Use the correct refmaps on Forge.
 - Prevent the Fabric jar pulling in some other mods.

Closes #1247

projects/forge/src/client/resources/computercraft-client.forge.mixins.json

@@ -1,13 +1,13 @@
 {
-    "minVersion": "0.8",
     "required": true,
-    "compatibilityLevel": "JAVA_17",
-    "refmap": "computercraft.mixins.refmap.json",
     "package": "dan200.computercraft.mixin.client",
+    "minVersion": "0.8",
+    "compatibilityLevel": "JAVA_17",
+    "injectors": {
+        "defaultRequire": 1
+    },
     "client": [
         "BlockRenderDispatcherMixin"
     ],
-    "injectors": {
-        "defaultRequire": 1
-    }
+    "refmap": "client-computercraft.refmap.json"
 }