Merge branch 'develop' into 16-ci-cd

.ci/.runlint.sh

.gitlab-ci.yml

clients.toml

database/database.go

gosdn-cli/gosdn-cli.go

gosdn.toml

log/logger.go

log/loglevel.go

main.go

nucleus/cli-handling.go

nucleus/controller.go

nucleus/interfaces/client.go

nucleus/interfaces/clientConfig.go

nucleus/nucleus-core.go

restconf/client/ciena/client.go

restconf/util/unmarshal.go