This might have an impact on disk usage for nodes with many incoming streams.

Add ansible-lint and fix all warnings and errors

See merge request !2

The autodetection seems buggy, see https://github.com/netdata/netdata/issues/10871

Normally, this files does not exist in `/etc/netdata`, so Netdata uses the default copy.
We need to copy the original first and then set the email variables, as the file also configures various other email variables.