Adding configurable telegraf parameters.
Allow to configurre remote endpoint/port/login/token
Proposed CLI:
```
set service monitoring telegraf authentication login 'log@in.local'
set service monitoring telegraf authentication token 'footokenfoo'
set service monitoring telegraf url 'foo.local:8086'
set service monitoring telegraf metrics daemons 'keepalived'
set service monitoring telegraf metrics daemons 'sshd'
```