Codec2: use std::list only for C2Work/C2Worklet

Use std::list for these as these are managed in lists.
onWorkDone now returns std::list<C2Work>
SettingsResult now contains std::vector<C2ParamFieldValues>
C2WorkOutline now contains std::vector<c2_node_id_t>

Bug: 64121714
Change-Id: Ibda75aad004be542c960cd190e19c168c5e3f724
6 files changed