cmd/node: configuration changes for genesis id

[evt]

Motivation

Closes #3505

Changes

Adds a genesis section into config.

DevOps Notes

• [x] This PR does not require configuration changes (e.g., environment variables, GitHub secrets, VM resources)
• [x] This PR does not affect public APIs
• [x] This PR does not rely on a new version of external services (PoET, elasticsearch, etc.)
• [x] This PR does not make changes to log messages (which monitoring infrastructure may rely on)

[evt]

changes in the vm module needs to be removed also please drop all that DefaultSomethingSomething. please keep only DefaultConfig. DefaultTestnetConfig and DefaultFastnetConfig should be written in presets files

vm changes removed. DefaultTestnetConfig - done. DefaultFastnetConfig - do we have it?

[evt]

bors try

[bors[bot]]

try

Build succeeded:

• ci-stage2

[dshulyak]

implemented elsewhere