Rename "backend" package to "core"

core/targetLocationFormatUNIX.go

@@ -0,0 +1,8 @@
+//go:build !windows
+
+package core
+
+// TargetLocationFormat returns the full location of an entry (given the name) formatted for the current platform
+func TargetLocationFormat(targetLocationIncomplete string) string {
+	return EntryRoot + targetLocationIncomplete
+}