NetMessages allocate a lot

[metalgearsloth]

https://github.com/space-wizards/RobustToolbox/pull/4582 is a bandaid but ideally we would just have stackalloced Span or something and write into NetBuffer without 1 morbillion allocations and not have to use RecycleableIOMemoryStream.

[metalgearsloth]

Also realistically we probably need to pass in the netmessage directly to PVS for writing comp states probably which would also avoid boxing the componentstate structs among other things.