An empty comment on new hosts is displayed as None in the overview view

[elnappo]

The default value of this field should be '' and not None. Guess we should set null=false here https://github.com/nsupdate-info/nsupdate.info/blob/4581f90f2d9bbb7a05e968a912c56692113bc4e8/src/nsupdate/main/models.py#L178