Add database schema management using Alembic

This patch replaces contrib/realtime/ with a new setup for managing the
database schema required for database integration with Asterisk.  In
addition to initializing a database with the proper schema, alembic can do a
database migration to assist with upgrading Asterisk in the future.
Hopefully this helps make setting up and operating Asterisk with a database
easier.

With this the schema only needs to be maintained in one place instead of
once per database.  The schemas I have added here have a bit of improvement
over the examples that were there before (some added consistency and added
some missing indexes).  Managing the schema in one place here also applies
to all databases supported by SQLAlchemy.

See contrib/ast-db-manage/README.md for more details.

Review: https://reviewboard.asterisk.org/r/2731

patch by Russell Bryant (license 6300)



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/12@397874 65c4cc65-6c06-0410-ace0-fbb531ad65f3

contrib/realtime/mysql/iaxfriends.sql

@@ -1,56 +0,0 @@
-#
-# Table structure for table `iaxfriends`
-#
-
-CREATE TABLE `iaxfriends` (
-  `name` varchar(40) NOT NULL default '',
-  `type` varchar(10) NOT NULL default 'friend', -- friend/user/peer
-  `username` varchar(40) NULL, -- username to send as peer
-  `mailbox` varchar(40) NULL, -- mailbox@context
-  `secret` varchar(40) NULL,
-  `dbsecret` varchar(40) NULL, -- In AstDB, location to store/retrieve secret
-  `context` varchar(40) NULL,
-  `regcontext` varchar(40) NULL,
-  `host` varchar(40) NULL default 'dynamic',
-  `ipaddr` varchar(40) NULL, -- Must be updateable by Asterisk user
-  `port` int(5) NULL, -- Must be updateable by Asterisk user
-  `defaultip` varchar(20) NULL,
-  `sourceaddress` varchar(20) NULL,
-  `mask` varchar(20) NULL,
-  `regexten` varchar(40) NULL,
-  `regseconds` int(11) NULL, -- Must be updateable by Asterisk user
-  `accountcode` varchar(20) NULL, 
-  `mohinterpret` varchar(20) NULL, 
-  `mohsuggest` varchar(20) NULL, 
-  `inkeys` varchar(40) NULL, 
-  `outkey` varchar(40) NULL, 
-  `language` varchar(10) NULL, 
-  `callerid` varchar(100) NULL, -- The whole callerid string, or broken down in the next 3 fields
-  `cid_number` varchar(40) NULL, -- The number portion of the callerid
-  `sendani` varchar(10) NULL, -- yes/no
-  `fullname` varchar(40) NULL, -- The name portion of the callerid
-  `trunk` varchar(3) NULL, -- Yes/no
-  `auth` varchar(20) NULL, -- RSA/md5/plaintext
-  `maxauthreq` varchar(5) NULL, -- Maximum outstanding AUTHREQ calls {1-32767}
-  `requirecalltoken` varchar(4) NULL, -- yes/no/auto
-  `encryption` varchar(20) NULL, -- aes128/yes/no
-  `transfer` varchar(10) NULL, -- mediaonly/yes/no
-  `jitterbuffer` varchar(3) NULL, -- yes/no
-  `forcejitterbuffer` varchar(3) NULL, -- yes/no
-  `allow` varchar(200) NULL, -- all/{list-of-codecs}
-  `codecpriority` varchar(40) NULL, 
-  `qualify` varchar(10) NULL, -- yes/no/{number of milliseconds}
-  `qualifysmoothing` varchar(10) NULL, -- yes/no
-  `qualifyfreqok` varchar(10) NULL, -- {number of milliseconds}|60000
-  `qualifyfreqnotok` varchar(10) NULL, -- {number of milliseconds}|10000
-  `timezone` varchar(20) NULL, 
-  `adsi` varchar(10) NULL, -- yes/no
-  `amaflags` varchar(20) NULL, 
-  `setvar` varchar(200) NULL, 
-  PRIMARY KEY  (`name`),
-  INDEX name (name, host),
-  INDEX name2 (name, ipaddr, port),
-  INDEX ipaddr (ipaddr, port),
-  INDEX host (host, port)
-);
-