app_confbridge: Add the ability to pass options/command to MixMonitor

This patch adds the ability to pass options and a command to MixMontor when
recording a conference using ConfBridge.

New options are -

* record_options: Options to MixMontor, eg: m(), W() etc.
* record_command: The command to execute when recording is over.
* record_file_timestamp: Append the start time to the file name.

These options can also be used with the CONFBRIDGE function, e.g.,
Set(CONFBRIDGE(bridge,record_command)=/path/to/command ^{MIXMONITOR_FILENAME}))

Review: https://reviewboard.asterisk.org/r/4023

ASTERISK-24351 #close
Reported by: Gareth Palmer
patches:
  record_command-428838.patch uploaded by Gareth Palmer (License 5169)



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@429934 65c4cc65-6c06-0410-ace0-fbb531ad65f3

CHANGES

@@ -12,6 +12,21 @@
 --- Functionality changes from Asterisk 13 to Asterisk 14 --------------------
 ------------------------------------------------------------------------------
 
+Applications
+------------------
+
+ConfBridge
+------------------
+ * Added the ability to pass options to MixMonitor when recording is used with
+   ConfBridge. This includes the addition of the following configuration
+   parameters for the 'bridge' object:
+   - record_file_timestamp: whether or not to append the start time to the
+     recorded file name
+   - record_options: the options to pass to the MixMonitor application
+   - record_command: a command to execute when recording is finished
+   Note that these options may also be with the CONFBRIDGE function.
+
+
 Channel Drivers
 ------------------