app_rpt: Be able to execute dialplan on nodes instead of "localplay"

[InterLinked1]

The rpt localplay command allows for playing audio files onto a node. This is used by functionality such as: https://github.com/AllStarLink/ASL3/pull/101/files

More flexible would be the ability to execute arbitrary dialplan on a node in the same contexts (e.g. localexec), which could play audio or do other stuff. This would eliminate a lot of duplicated functionality in Asterisk in the ASL repos, such as constructing and playing the time, when there are Asterisk applications that already do the same things.