Some issues spotted (#145)

This PR lists some issues and suggested fixes for them (feel free to
pick them up separately and close this PR):

In addition to issues outlined in
https://github.com/paritytech/zombienet-sdk/issues/117#issuecomment-1867941395,
here are some issues spotted when writing
https://github.com/paritytech/disabling-e2e-tests:
- runtime genesis patch is applied incorrectly (extra `/genesis` pointer
shouldn't be added)
- malus accepts
[subcommands](https://github.com/paritytech/polkadot-sdk/blob/4c0e0e071355c1048d75fba538c96c35ac743547/polkadot/zombienet_tests/functional/0008-dispute-old-finalized.toml#L25),
having a command with spaces not supported, so I added a subcommand
support
- some types need to be exported in order to be able to reuse
setup/helper functions across multiple tests
- test cleanup doesn't always work (zombie polkadot processes - not
fixed here)

---------

Co-authored-by: Javier Viola <363911+pepoviola@users.noreply.github.com>