Allow dashes Barman::ServerName type

[shamil]

I think allowing - in server name is legit.
Also, question regarding $description option for the below, requires to be of type Barman::ServerName, which limits what can be put as description. I think description should have be allowed a free text, with spaces, etc ...

puppet-barman/manifests/postgres.pp

Line 250 in 89869bc

Barman::ServerName $description = $name,

and

puppet-barman/manifests/server.pp

Line 201 in 89869bc

Barman::ServerName $description = $name,

I can add a change that allows to have more permissive $description, lmk.

[deric]

You're right the types are too restrictive. $description should be just String. Thanks for the PR!