Rename OrmException to StorageException and move to exceptions package

Subclasses are also renamed:
 * OrmDuplicateKeyException -> DuplicateKeyException
 * OrmRuntimeException -> StorageRuntimeException

Change-Id: I0e934f177e98667ec7cb9912f246ac649a4efd99

plugins/BUILD

@@ -31,6 +31,7 @@ EXPORTS = [
     "//antlr3:query_parser",
     "//java/com/google/gerrit/common:annotations",
     "//java/com/google/gerrit/common:server",
+    "//java/com/google/gerrit/exceptions",
     "//java/com/google/gerrit/extensions:api",
     "//java/com/google/gerrit/git",
     "//java/com/google/gerrit/index",
@@ -50,7 +51,6 @@ EXPORTS = [
     "//java/com/google/gerrit/server/util/time",
     "//java/com/google/gerrit/util/cli",
     "//java/com/google/gerrit/util/http",
-    "//java/com/google/gwtorm",
     "//lib/antlr:java-runtime",
     "//lib/auto:auto-value-annotations",
     "//lib/commons:compress",