Investigate slight increase in memory consumption during Mainnet catchup

**Task description**
Comparing memory consumption results collected during Mainnet catch-up preformed with 4.4.3 and 5.1.3 have shown a slight increase in memory consumption.

All the measurements were done on the same machine which runs on Ubuntu. Catching up from peers from height 0.
Memory was measured with top `top -e M -d 1 | grep concordium --line-buffered > mem.log`

Results are available here: https://docs.google.com/spreadsheets/d/1K5ina6doYvZXE2hqKLE7BiwIQelZe5KETsYZzZpqOhE/edit#gid=0

**Sub-tasks**
- [ ] subtask 1
- [ ] subtask 2
- [ ] subtask 3

*Add label for component and priority.*

Review the linked memory measurements and reproduce Mainnet catch-up from height 0 on Ubuntu using the stated top command. Compare the 4.4.3 and 5.1.3 results, then identify and document the source of the increased consumption; the issue names no source files or tests to begin with.

Written by the indexing model from the issue text.