Java: Add upgrade and downgrade script

Author: IdrissRio

java/downgrades/07cb766b3876cda17a74f9071a851a1a410d4db2/old.dbscheme

@@ -0,0 +1,3 @@
+description: Remove moduleImportDeclarations relation
+compatibility: full
+moduleImportDeclarations.rel: delete

java/downgrades/07cb766b3876cda17a74f9071a851a1a410d4db2/semmlecode.dbscheme

@@ -1,3 +1,4 @@
 description: Add overlayChangedFiles relation
-compatibility: full
-overlayChangedFiles.rel: delete
+compatibility: partial
+moduleImportDeclarations.rel: delete
+imports.rel: run imports.qlo

java/downgrades/07cb766b3876cda17a74f9071a851a1a410d4db2/upgrade.properties

@@ -0,0 +1,12 @@
+class Import extends @import {
+  string toString() { none() }
+}
+
+class ClassOrInterfaceOrPackage extends @classorinterfaceorpackage {
+  string toString() { none() }
+}
+
+from Import imp, ClassOrInterfaceOrPackage holder, string name, int kind
+where
+  imports(imp, holder, name, kind) // Keep all existing imports as-is
+select imp, holder, name, kind