Add "serviceName" and "serviceType" to bot and chat logger

Summary:
Make each adapter provide a "serviceType" (campfire, flowdock, IRC) and "serviceName" (irc network / chat server) so that we can disambiguate between, e.g., "#phabricator on EFNet" and "#phabricator on FreeNode".

Make the chatlog handler ship them over Conduit.

Also fix some "policy can not be null" bugs with chatlog recording.

Test Plan:
Verified data inserted correctly:

  mysql> select * from chatlog_channel;
  +----+------------------+-------------+--------------+------------+------------+-------------+--------------+
  | id | serviceName      | serviceType | channelName  | viewPolicy | editPolicy | dateCreated | dateModified |
  +----+------------------+-------------+--------------+------------+------------+-------------+--------------+
  |  1 | irc.freenode.net | IRC         | #phabricator | users      | users      |  1361201689 |   1361201689 |
  +----+------------------+-------------+--------------+------------+------------+-------------+--------------+
  1 row in set (0.00 sec)

  mysql> select * from chatlog_event where channelID = 1;
  +----+--------------+------------+------------+------+---------------+--------------------------------+-----------+
  | id | channel      | epoch      | author     | type | message       | loggedByPHID                   | channelID |
  +----+--------------+------------+------------+------+---------------+--------------------------------+-----------+
  | 45 | #phabricator | 1361201689 | epriestley | mesg | blip blip     | PHID-USER-5bt2phfepag4cdvjtzg5 |         1 |
  | 46 | #phabricator | 1361201700 | epriestley | mesg | boop boop bip | PHID-USER-5bt2phfepag4cdvjtzg5 |         1 |
  +----+--------------+------------+------------+------+---------------+--------------------------------+-----------+
  2 rows in set (0.00 sec)

Reviewers: Afaque_Hussain, indiefan

Reviewed By: Afaque_Hussain

CC: aran

Maniphest Tasks: T837

Differential Revision: https://secure.phabricator.com/D4996