Optimization: copy of a packet is not stored by mesh protocol, but requested as necessary

[divanchykhin]

This optimization is applicable rather for terminal devices where GDP already keeps its copy of a packet. In general (up to particular calls) it's possible to ask GDP to provide that copy (unchanged), to supply it 9together with input parameters used last time) to SP, etc, and to get what otherwise we would have to store on MESH level.
Another variation of this optimization is to cause GDP to re-send the packet in a regular way.