chore: add build gradle kts for kotlin dsl and dependencies

Author: OmarAlJarrah

buildSrc/build.gradle.kts

@@ -0,0 +1,15 @@
+repositories {
+    mavenCentral()
+    maven {
+        url = uri("https://oss.sonatype.org/content/repositories/snapshots/")
+    }
+}
+
+plugins {
+    `kotlin-dsl`
+}
+
+dependencies {
+    api("org.openapitools:openapi-generator:7.11.0")
+    implementation("com.samskivert:jmustache:1.15")
+}