Switch from Parity Ethereum to SputnikVM

[artob]

I am evaluating changing near-evm-runner to use [SputnikVM](https://github.com/rust-blockchain/evm) instead of Parity Ethereum, so as to align with the latest [EVM-as-a-contract](https://github.com/near/near-evm) developments, give us an upgrade path, improve performance, and reduce spurious third-party dependencies (and their license issues).

Related issue: near/near-evm#57

[stale]

This issue has been automatically marked as stale because it has not had recent activity in the last 2 months.
It will be closed in 7 days if no further activity occurs.
Thank you for your contributions.