route53: check permissions to perform route53:ListResourceRecordSets

otherwise, at install time we see "DNS credentials for xx are invalid. Update it in Domains & Certs view"

the exact error from route 53 is:

User: arn:aws:iam::xx:user/yy is not authorized to perform: route53:ListResourceRecordSets on resource: arn:aws:route53:::hostedzone/zz because no identity-based policy allows the route53:ListResourceRecordSets action

src/dns/route53.js

@@ -255,6 +255,9 @@ async function verifyDomainConfig(domainObject) {
     await upsert(newDomainObject, location, 'A', [ ip ]);
     debug('verifyDomainConfig: Test A record added');
 
+    await get(newDomainObject, location, 'A');
+    debug('verifyDomainConfig: Can list record sets');
+
     await del(newDomainObject, location, 'A', [ ip ]);
     debug('verifyDomainConfig: Test A record removed again');