Upgrade CI pipelines' default Node.js version to v16 (Latest LTS)

[achrinza]

Node.js v16 was transitioned to "Active LTS" status with v16.13.0 on 26 October 2021. As part of standard practice, the CI pipelines' "default" Node.js version shall be bumped to v16.

Repos to be updated:

• loopback-next (PR: ci: default to Node.js v16 loopback-next#8088, ci: enable Windows testing on Node.js v16 loopback-next#8102)
• loopback4-example-shopping (PR: ci: update Node.js verisons loopback4-example-shopping#1381)
• loopback-connector (PR: ci: update envirnoment loopback-connector#192)
• loopback-connector-cassandra
• loopback-connector-cloudant
• loopback-connector-couchdb2
• loopback-connector-db2
• loopback-connector-dashdb
• loopback-connector-elastic-search
• loopback-connector-grpc (PR: Pin NPM; Update Node.js loopback-connector-grpc#17)
• loopback-connector-ibmi
• loopback-connector-kv-extreme-scale
• loopback-connector-kv-redis
• loopback-connector-mongodb
  • v6.x (PR: Pin NPM, Update Node.js loopback-connector-mongodb#652)
  • v5.x (Not applicable)
• loopback-connector-mysql
• loopback-connector-openapi
• loopback-connector-oracle
• loopback-connector-postgresql
• loopback-connector-redis
• loopback-connector-rest
• loopback-connector-soap
• loopback-connector-sqlite3
• loopback-datasource-juggler
• loopback-extension-grpc
• loopback-ibmdb
• strong-soap (PR: ci: update environment strong-soap#347)

Post-issue todo:

• Update https://github.com/achrinza/loopback-framework-ci-status/blob/9372f902431aade29ec39ba672d125c1dbcb9ad9/README.md