Support PoS data size more than 2-4kb

[brusherru]

Description

Right now go-spacemesh supports only numUnits that are equal to 2KB, 3KB, and 4KB. We want to make it possible to set up a bigger PoS data size (up to a few GB?) and test it as well.

The node implements GRPC endpoint SmesherService.PostConfig, which returns minNumUnits and maxNumUnits. Besides this, the node does not start smeshing (but syncing well) if numunits property specified in the node config is out of the range, and logs an error:

{"L":"ERROR","T":"2022-08-03T15:41:35.299+0300","N":"00000.defaultLogger","M":"failed to start smeshing: failed to start post setup session: new initializer: invalid `opts.NumUnits`; expected: <= 4, given: 4000"}

I think this is OK, so we just need to tweak min/maxNumUnits values ;)

Steps to reproduce

1. Open node-config.json
2. Change numUnits to some value greater than 4
3. Run the node

Environment

• Node Version: 0.2.17-beta.0

[moshababo]

MinNumUnits and MaxNumUnits are network params. NumUnits, picked by the user, must be in the range. The values you mentioned look like test params. Where are they taken from?

[pigmej]

This obviously first need finished parametrization. Then we set whatever is a result of parametrization.

[pigmej]

The implementation is finished with the post-rs. Now awaiting parametrization.