Now that the IPv4Address has the ability to generate valid IP addresses
from CIDR notations, this provides a nicer interface to the user when
specifying the network address to add or delete.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
