minor, safe-guard QMETA packer and checker in svc-uterus

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
fix, PEBKAC, actually send data off the buffer we're filling in um_pack_brag()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/svc-uterus' into next

* feat/svc-uterus:
  fix, PEBKAC, actually send data off the buffer we're filling in um_pack_brag()
  minor, safe-guard QMETA packer and checker in svc-uterus
minor, migrate um-xmit tool to new unserding api

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
hygiene, replace meta bang in shout_syms() by bang_qmeta() helper fun

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'feat/new-ud-api/xmit' into next

* feat/new-ud-api/xmit:
  hygiene, replace meta bang in shout_syms() by bang_qmeta() helper fun
  minor, migrate um-xmit tool to new unserding api