Add support for brackets (begingroup, endgroup) between processes

[ERnsTL]

• this issue is about support for brackets between processes (between runtime and clients, there is network:beginbracket and between runtimes, there is runtime:packet with event "beginbracket")
• need to have a way to mark these out-of-band, meaning NOT using some in-band "magic value"
• yes, definitely out of band otherwise this adds injection attacks
• JPM's JavaFBP does it OOB
  • they are called open bracket and close bracket.
  • and the packet itself contains the name of the group in the object structure. Nifty.
• the FBP JSON Graph protocol also does it OOB
• no way around changing the IP struct from Vec to a struct with the type field denoting normal, open bracket/begingroup, close bracket/endgroup.