[FAB-12176] Private data and metadata writes
[FAB-12176] Private data and metadata writes

This fix lets the gossip private data coordinator recognize not only
regular writes to private data keys, but also updates of the metadata.

Change-Id: I41ac4dcdc929e1d2390a1eb75684d01c37264f4c
Signed-off-by: Matthias Neugschwandtner <e570e5dc4777cc7f93f0f6ac0d7f23388ed99ae3@zurich.ibm.com>

manish-sethi/fabric-sidedb,hyperledger/fabric,binhn/fabric,manish-sethi/fabric,muralisrini/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,stemlending/fabric,binhn/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,xixuejia/fabric,stemlending/fabric,muralisrini/fabric,xixuejia/fabric,xixuejia/fabric,manish-sethi/fabric,stemlending/fabric,jimthematrix/fabric,stemlending/fabric,muralisrini/fabric,jimthematrix/fabric,manish-sethi/fabric-sidedb,binhn/fabric,hyperledger/fabric