dnsdist: Add `QNameLabelsCountRule()` and `QNameWireLengthRule()`

dnsdist: Add `QNameLabelsCountRule()` and `QNameWireLengthRule()`

* QNameLabelsCountRule(min, max) matches if the qname has less than
min or more than max labels.
* QNameWireLengthRule(min, max) matches if the qname's length on the
wire is less than min or more than max bytes.
* Also add Lua bindings for DNSName's `countLabels()` and `wirelength()`