Add Wildcard Record detection

[junnlikestea]

Currently the wildcard detection is just a naive check on the label of the record and isn't very effective.

reesolve/src/data.rs

Line 163 in 22585f8

let is_wildcard = record.name().is_wildcard();

The proposed implementation takes the contents of ResultsCache and appends a canary string to each record in the cache , then attempts to resolve it. If it resolves we mark it as a wildcard record. For example, we have some record named example.com we then add the canary cmVlc29sdmVjYW5hcnk.example.com and attempt to resolve that record.

reesolve/src/resolver.rs

Lines 278 to 282 in c8f023d

	let wildcard = format!("{}.{}", CANARY, name);
	if resolver.lookup_ip(wildcard).await.is_ok() {
	info!("{} is wildcard record", &key);
	// Only acquire the lock if we've found a wildcard
	cache.set_wildcard(&key).await;

The cache.set_wildcard method just acquires the lock and modifies the is_wildcard to be true

reesolve/src/data.rs

Lines 49 to 59 in c8f023d

	pub(crate) async fn set_wildcard(&self, key: &str) {
	let mut lock = self.inner.lock().await;
	if let Some(record) = lock.get_mut(key) {
	if let ResolveResponse::IpRecord { is_wildcard, .. }
	| ResolveResponse::Record { is_wildcard, .. } = record
	{
	*is_wildcard = true;
	}
	}
	}