gradle: add properties and modify injected-client (#1145)

* add implementation for getItemCount

* Ignore build directory in project root

* save injector results as class files

* package injected-client for shading into client

* auto-updating properties

* fix run task

* shade injected-client into jar

.gitignore

@@ -14,7 +14,7 @@ classes/artifacts/client_jar/run.bat
 classes/artifacts/client_jar/client.jar
 *.jar
 .live/
-*/build/
+**/build/*
 */out/
 .gradle/
 runelite-client/src/main/resources/runelite/*