The new vty option "rtp hr-format (rfc5993|ts101318)" selects the
RTP output format to be used for HR1 codec, consistently across
all models. The default is set to match legacy behavior: ts101318
on osmo-bts-{lc15,oc2g,sysmo} and rfc5993 on osmo-bts-trx.
On models where no legacy behavior is applicable, the default is
set to rfc5993 as a forward-looking measure - see OS#6036.
Closes: OS#5688
Change-Id: I168191874a062429a57904511a1e89e3f588732e