Create a type UsizeSer32(pub usize) and use it for all u32 BlockDocument fields

added D-easy label

changed milestone to %v0.4 Full Mirror Node

changed milestone to %v0.5 Full mirror node with mempool

We should create this special type in the durs-common-tools crate, it has already been done for the WotId type defined in lib/dubp/wot/data/mod.rs, just copy/paste the code and rename the type (then use it).

assigned to @dvermd

added S-doing label

created merge request !270 (merged) to address this issue

mentioned in merge request !270 (merged)

closed via merge request !270 (merged)