Do a long test with a load pool can handle

We can see that memory is slightly increasing during a load that pool can handle.
We suspect that there can be a limit where it's cut off, but in order to prove it we need to run a long test.

Increasing memory consumption may be caused by RocksDB (see comments in INDY-1724).

Acceptance Criteria:

• Run load script with 1-10 NYMs per second for 2-3 days.
• Check graphs for memory consumption