chore: organize homework into first-part directory

first-part/hw-03/project-root/gradle/libs.versions.toml

@@ -0,0 +1,8 @@
+# This file was generated by the Gradle 'init' task.
+# https://docs.gradle.org/current/userguide/version_catalogs.html#sec::toml-dependencies-format
+
+[versions]
+guava = "33.5.0-jre"
+
+[libraries]
+guava = { module = "com.google.guava:guava", version.ref = "guava" }