Support for project namespaces

Main issue: https://projects.task.gda.pl/monitoring/monitoring/issues/128

The following changes should be made:

• new variable: telegraf_project (required)
• all measurement names changed to include telegraf_project as a prefix, e.g. cpu → {{ telegraf_project }}_cpu
• configuration directory changed to include telegraf_project as a sufix, i.e. /etc/telegraf → /etc/telegraf-{{ telegraf_project }}
• service name changed to include telegraf_project as a sufix, i.e. telegraf.service → telegraf-{{ telegraf_project }}.service