Added Gradle + removed IDEA files.

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settings.gradle.kts

@@ -0,0 +1,10 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * The settings file is used to specify which projects to include in your build.
+ *
+ * Detailed information about configuring a multi-project build in Gradle can be found
+ * in the user manual at https://docs.gradle.org/6.6.1/userguide/multi_project_builds.html
+ */
+
+rootProject.name = "Terra"