Add the Pair class since Map.Entry<?, ?> doesn't deserialize in Jackson
automatically or easily and we don't want to include a library like Apache
Commons for a single class.
Tweak ByteArrayPair to use the Pair class
Cleanup Tags class
Extend SearchQuery for lookups with a metric and a tags field.
Modify TimeSeriesLookup to use SearchQuery
Implement /api/search/lookup in the SearchRpc class
Add the Search CLI tool