(chore): Parametrize number of nodes

We can parametrize the number of consensus instances we launch using malachite's spawn script but we cannot vary the number of reth nodes beyond 4.

Currently, for every node we have hardcoded the setup in a `compose.yml` file.

Ideally, we want to also be able to pass reth config params rather than hardcoding them in the compose file.

What needs to be done:

- have a reth.conf file with:
- all the reth cli flags we want to pass on to container on boot up.
- prefix for reth URLs - the ports will be appended afterwards
- path to reth.toml as we will need to send a custom reth.toml file to configure node pruning (it is passed to reth via `--config path_to_file` . This file can be stored in `.assets` alongside the jwt secret so we do not need to mount another folder.
- based on the number of nodes defined via CLI (see #77 ) and the content of `reth.conf` we fill up the `compose.yaml` file for docker.