Refactor template using buildSrc, feature variants and published version catalogs (#56)

Co-authored-by: Abe Pazos <abe@hamoid.com>

buildSrc/build.gradle.kts

@@ -0,0 +1,12 @@
+plugins {
+    `kotlin-dsl`
+}
+
+val libs = extensions.getByType<VersionCatalogsExtension>().named("libs")
+
+dependencies {
+    implementation(libs.findLibrary("shadow-gradle-plugin").get())
+    implementation(libs.findLibrary("runtime-gradle-plugin").get())
+    implementation(libs.findLibrary("kotlin-gradle-plugin").get())
+    implementation(libs.findLibrary("xversions-gradle-plugin").get())
+}