* Update proto file with Tx 'estimated gas used' field
* Update tx_counter according to tx gas quota
* Feature/user spam limit checks (#47)
* Print proof generation error before sending it
* Check user spam limit in grpc send_transaction endpoint
* Move all code related to smart contracts into lib smart_contract
* Can start the prover with mocked smart contract
* Add KarmaTier integration
* Filter & validate initial tier limits
* Add initial code for user db (user reg + tx counter + tier info)
* Switch to scc hashmap (+ updated benchmark)
* Add KSC into UserDB
* Start user db service in prover main
* Separate between user db service & user db
* Add set tier limits grpc endpoint
* Set tier limits unit test
* Use derive_more