✨ Convert build scripts to Kotlin

Also added some new tasks to only build/install to maven local certain platforms
`buildMinecraft`, `installMinecraft`, `buildDiscord`, `installDiscord`, `buildIRC`, `installIRC`

cloud-kotlin-extensions/build.gradle.kts

@@ -0,0 +1,37 @@
+import org.jetbrains.dokka.gradle.DokkaTask
+import java.net.URL
+
+plugins {
+    kotlin("jvm") version "1.4.21-2"
+    id("org.jetbrains.dokka") version "1.4.20"
+}
+
+tasks {
+    withType<DokkaTask>().configureEach {
+        dokkaSourceSets.getByName("main") {
+            includes.from(layout.projectDirectory.file("src/main/descriptions.md").toString())
+            externalDocumentationLink {
+                url.set(URL("https://javadoc.commandframework.cloud/")) //todo fix KDoc linking to JavaDoc
+                packageListUrl.set(URL("https://javadoc.commandframework.cloud/allpackages-index.html"))
+            }
+        }
+    }
+    javadocJar {
+        from(dokkaHtml)
+    }
+    compileKotlin {
+        kotlinOptions.jvmTarget = "1.8"
+    }
+    compileTestKotlin {
+        kotlinOptions.jvmTarget = "1.8"
+    }
+}
+
+kotlin {
+    explicitApi()
+}
+
+dependencies {
+    api(project(":cloud-core"))
+    testImplementation("org.jetbrains.kotlin", "kotlin-test-junit5")
+}