Move datagen to its own source set

MC 1.21.4 means we have to move more data generation code into the
client source set. Given all this code movement, it probably makes sense
to put data generation in a separate source set instead.

1.21.4 also has split data generators for client and server, but neither
mod loader recommends this. This means we can/should merge DataProviders
and ClientDataProviders into a single class.

Data generators are no longer bundled with the jar, which does reduce
file size, but by a tiny amount (~70KiB).

projects/fabric/build.gradle.kts

@@ -8,7 +8,7 @@ import java.util.*
 
 plugins {
     id("cc-tweaked.fabric")
-    id("cc-tweaked.gametest")
+    id("cc-tweaked.mod")
     id("cc-tweaked.mod-publishing")
 }
 
@@ -146,6 +146,8 @@ loom {
             configName = "Datagen"
             client()
 
+            source(sourceSets.datagen.get())
+
             runDir("run/dataGen")
             property("fabric-api.datagen")
             property("fabric-api.datagen.output-dir", layout.buildDirectory.dir("generatedResources").getAbsolutePath())

projects/fabric/src/datagen/java/dan200/computercraft/data/FabricDataProviders.java

@@ -26,7 +26,7 @@ import java.util.concurrent.CompletableFuture;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
-public class FabricDataGenerators implements DataGeneratorEntrypoint {
+public class FabricDataProviders implements DataGeneratorEntrypoint {
     @Override
     public void onInitializeDataGenerator(FabricDataGenerator generator) {
         var pack = new PlatformGeneratorsImpl(generator.createPack());

projects/fabric/src/datagen/resources/fabric.mod.json

@@ -0,0 +1,13 @@
+{
+    "schemaVersion": 1,
+    "id": "cc-datagen",
+    "version": "1.0.0",
+    "entrypoints": {
+        "fabric-datagen": [
+            "dan200.computercraft.data.FabricDataProviders"
+        ]
+    },
+    "depends": {
+        "computercraft": "*"
+    }
+}

projects/fabric/src/main/resources/fabric.mod.json

@@ -23,9 +23,6 @@
         "client": [
             "dan200.computercraft.client.ComputerCraftClient::init"
         ],
-        "fabric-datagen": [
-            "dan200.computercraft.data.FabricDataGenerators"
-        ],
         "jei_mod_plugin": [
             "dan200.computercraft.client.integration.jei.JEIComputerCraft"
         ],

projects/fabric/src/testMod/resources/fabric.mod.json

@@ -1,6 +1,6 @@
 {
     "schemaVersion": 1,
-    "id": "cctest",
+    "id": "cc-datagen",
     "version": "1.0.0",
     "entrypoints": {
         "main": [