Add empty genesis block and remove init state

[mikiw]

Usage related changes

• An empty genesis block was added.

Development related changes

• An empty genesis block was added which caused some test changes.

Checklist:

• Checked the relevant parts of development docs
• Applied formatting - ./scripts/format.sh
• No linter errors - ./scripts/clippy_check.sh
• No unused dependencies - ./scripts/check_unused_deps.sh
• Performed code self-review
• Rebased to the latest commit of the target branch (or merged it into my branch)
• Updated the docs if needed, including the TODO section
• Linked the issues which this PR resolves
• Updated the tests if needed; all passing (execution info)

[mikiw]

I didn't self-review it but I think it's reviewable if someone has free time on Monday.

I still need to add documentation.

I consider the genesis block as block number zero, not the first block, just saying because some variables in tests has names likefirst_block.

[mikiw]

I quickly self-review it so it can be reviewed from a code perspective. I'll add the documentation on Tuesday.