Added RFC 3397 encoding for kea

_modules/kea.py

+
+def rfc3397(domains):
+    """
+    Return a RFC-3397 encoded string (without compression)
+
+    see https://tools.ietf.org/search/rfc3397
+
+    :param string[] domains: A list of domains
+    """
+
+    domain_list = ""
+    for domain in domains:
+        domain_list += ''.join(
+            map(lambda dom: chr(len(dom)) + dom, domain.strip().split('.'))
+        ) + "\0"
+    return domain_list.encode('utf-8').hex()