Replace anyjson with oslo.serialization

Now, when we started to use oslo.serialization it is safe
to replace all the usages of anyjson with jsonutils from
oslo library.
oslo.serialization uses anyjson under the hood, so there
shouldn't be any performance changes.

Change-Id: I8d6fbfbf88e657f5586c7361de849683c064d2e2
Merge "Replace anyjson with oslo.serialization"