In this change, we create a new package
com.google.gerrit.server.patch.filediff and moved some of the old diff
cache entities to it.
These entities (mainly the EditTransformer) will be used in the next
follow up change by the "File Diff" cache, which will be added to the
same package. The other moved entities (Edit, FileEdtis,
PatchListLoader) are also moved to the new package because they are used
by EditTransformer. Some access modifiers were temporarily changed from
package private to public because they depend on classes in
com.google.gerrit.server.patch.
Note that the PatchListEntry.java and PatchListLoader are
implementations of the old diff cache and should be deprecated after the
redesign.
Change-Id: I5830d57f6cbabefc4604036b58752836673657a5
429926afc7