res_pjsip_config_wizard: Add ability to auto-create hints.

Looking at the Super Awesome Company sample reminded me that creating hints is 
just plain gruntwork.  So you can now have the pjsip conifg wizard auto-create 
them for you.

Specifying 'hint_exten' in the wizard will create 
'exten => <hint_exten>,hint/PJSIP/<wizard_id>'
in whatever is specified for 'hint_context'.

Specifying 'hint_application' in the wizard will create
'exten => <hint_exten>,1,<hint_application>'
in whatever is specified for 'hint_context'.

The default for 'hint_context' is the endpoint's context.
There's no default for 'hint_application'.  If not specified, no app is added.
There's no default for 'hint_exten'.  If not specified, neither the hint itself 
nor the application will be created.

Some may think this is the slippery slope to users.conf but hints are a basic 
necessity for phones unlike voicemail, manager, etc that users.conf creates.

Tested-by: George Joseph
Review: https://reviewboard.asterisk.org/r/4383/
........

Merged revisions 431643 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@431644 65c4cc65-6c06-0410-ace0-fbb531ad65f3