Rename ProjectQueryBuilder.java to preserve history.

This change doesn't build - this is expected.

The next change introduces interface ProjectQueryBuilder, so this change
is required to preserve the history - otherwise, git doesn't detect
renaming.

Release-Notes:skip
Change-Id: I5f9437d11b8851a62a2477dccb62628a2265c8ee
diff --git a/java/com/google/gerrit/server/query/project/ProjectQueryBuilder.java b/java/com/google/gerrit/server/query/project/ProjectQueryBuilderImpl.java
similarity index 100%
rename from java/com/google/gerrit/server/query/project/ProjectQueryBuilder.java
rename to java/com/google/gerrit/server/query/project/ProjectQueryBuilderImpl.java