i-1: First draft of a shared KMP library (#2)

- [x] Exposes a `Greeting` class.
- [x] Exposes a `Greeting` class test.

Co-authored-by: Emil Simeonov <emil@theliberatededge.org>
Reviewed-on: emil/AstrologyLibrary#2

gradle.properties

@@ -0,0 +1,11 @@
+#Gradle
+org.gradle.jvmargs=-Xmx2048M -Dfile.encoding=UTF-8 -Dkotlin.daemon.jvm.options\="-Xmx2048M"
+org.gradle.caching=true
+org.gradle.configuration-cache=true
+
+#Kotlin
+kotlin.code.style=official
+
+#Android
+android.useAndroidX=true
+android.nonTransitiveRClass=true