[Snapshotter] Create a new Oracle contract for saving snapshots

[rattrap]

Validator perspective:

• Owner can add "validators" to the contract
• We need an index for the current "leader" (the validator that will upload the next snapshot)
• The "leader" uploads the snapshot, uploads the index file and calls the contract with the index file hash
• The other nodes act as verifiers and check the index file + hash
• Other nodes vote for the change and after 2/3 majority
• Increment the index for the leader and save the current snapshot as the latest

User perspective:

• Check if node is initialised
• Go to the contract and grab the latest index hash
• Download all of the files in the index file hash in the right path
• Rename them to db and state_db
• Start node

[VargaElod23]

Pls add the bullet points form ytday @rattrap

[rattrap]

@VargaElod23, done