Feature request: add the possibility to send FragSessionStatusReq via multicast rather than unicast

[nicolas-juteau]

Suggestion: add INBETWEEN_PARITY_FRAGMENTS to the RequestFragmentationSessionStatus enum.

If this mode is selected, the fuota server could behave like this:

The FUOTA server splits the parity fragments into N groups. After each group of parity fragments sent to the multicast group, the fuota server issues one or more (successive) multicast FragSessionStatusReq with participants bit NOT set. The FUOTA server continues sending groups of parity fragments, until either:

• configured parity fragments to send is exhausted
• no more FragSessionStatusAns are received from end-devices (indicating end-devices all successfully reconstructed the data block)
• multicast class-c session expires

[nicolas-juteau]

The following could also be configurable

• number of parity fragments in each group
• number of successive FragSessionStatusReq to send inbetween parity fragment groups