app_originate: Add ability to set codecs

A list of codecs to use for dialplan-originated calls can
now be specified in Originate, similar to the ability
in call files and the manager action.

Additionally, we now default to just using the slin codec
for originated calls, rather than all the slin* codecs up
through slin192, which has been known to cause issues
and inconsistencies from AMI and call file behavior.

ASTERISK-29543

Change-Id: I96a1aeb83d54b635b7a51e1b4680f03791622883