api: replace varbits enum with ints

This adds a Varbit magic constant annotation which is used now on
varbit parameters and fields.

This is roughly the same type-safety wise, with IDE support, but the ids
can be inlined by the compiler and it avoids having to have a large enum
class with many fields.

runelite-client/pom.xml

@@ -136,6 +136,12 @@
 			<groupId>com.google.code.findbugs</groupId>
 			<artifactId>jsr305</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>org.jetbrains</groupId>
+			<artifactId>annotations</artifactId>
+			<version>23.0.0</version>
+			<scope>provided</scope>
+		</dependency>
 
 		<!-- JOGL -->
 		<dependency>