Build using Toothpick scripts (#122)

Co-authored-by: BillyGalbreath <blake.galbreath@gmail.com>

buildSrc/src/main/kotlin/ToothpickExtensions.kt

@@ -0,0 +1,30 @@
+import org.gradle.api.Project
+import org.gradle.kotlin.dsl.findByType
+import java.io.File
+import java.nio.file.Path
+
+val Project.toothpick: ToothpickExtension
+    get() = rootProject.extensions.findByType(ToothpickExtension::class)!!
+
+fun Project.toothpick(receiver: ToothpickExtension.() -> Unit) {
+    toothpick.project = this
+    receiver(toothpick)
+    allprojects {
+        group = toothpick.groupId
+        version = "${toothpick.minecraftVersion}-${toothpick.nmsRevision}"
+    }
+    configureSubprojects()
+    initToothpickTasks()
+}
+
+val Project.lastUpstream: File
+    get() = rootProject.projectDir.resolve("last-${toothpick.upstreamLowercase}")
+
+val Project.rootProjectDir: File
+    get() = rootProject.projectDir
+
+val Project.upstreamDir: File
+    get() = rootProject.projectDir.resolve(toothpick.upstream)
+
+val Project.projectPath: Path
+    get() = projectDir.toPath()