Fix build break

New version of grpc-js required 'fs/promises', which does not exist in
the particular version of Node 12 included in the
hyperledger/fabric-nodeenv:2.2 image. It does exist in later releases of
Node 12.

This change configures the peer to use the v2.5 Node chaincode
container, which uses a later Node version. It also includes
npm-shrinkwrap.json files for the Node chaincode used by the scenario
tests to avoid any unexpected future dependency version resolution
changes.

Signed-off-by: Mark S. Lewis <Mark.S.Lewis@outlook.com>

.gitignore

@@ -5,7 +5,6 @@
 coverage
 docs/gen
 node_modules
-npm-shrinkwrap.json
 npm-debug.log
 yarn.lock
 tmp