Refactor source layout

Introduce compat source sets and move all kotlin sources to the main directory

[no changelog]

src/main/kotlin/util/IdentifierSerializer.kt

@@ -0,0 +1,25 @@
+
+package moe.nea.firmament.util
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import net.minecraft.util.Identifier
+
+object IdentifierSerializer : KSerializer<Identifier> {
+    val delegateSerializer = String.serializer()
+    override val descriptor: SerialDescriptor
+        get() = PrimitiveSerialDescriptor("Identifier", PrimitiveKind.STRING)
+
+    override fun deserialize(decoder: Decoder): Identifier {
+        return Identifier.of(decoder.decodeSerializableValue(delegateSerializer))
+    }
+
+    override fun serialize(encoder: Encoder, value: Identifier) {
+        encoder.encodeSerializableValue(delegateSerializer, value.toString())
+    }
+}