Ability to set tags during installation and enrolment agent
so that different identical deployments of service can be differentiated in the dataset

The specific use case is described in: https://discuss.elastic.co/t/fleet-managed-elastic-agent-environment-deployment-name-custom-field/282565/6

sudo ./elastic-agent install -f --url=https://<feet manager>:443 --enrollment-token=<token> --tag=staging01 

or in case, the agent is already installed via package manager

elastic-agent enroll -f --url=https://<feet manager>:443 --enrollment-token=<token> --tag=staging01