Add support for BeaconProxy pattern

[nikitosing]

Close #4770

Changelog

Enhancements

• Added support for BeaconProxy smart-cotract pattern

If some smart-contract (BeaconProxy) has address (pointing to the Beacon) at the storage slot bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1, then we call implementation() method from the Beacon. We consider address returned by implementation() at the Beacon contract as address of the implementation of BeaconProxy. If call for some reason failed, we return address of the Beacon as the implementation.

Checklist for your Pull Request (PR)

• I added an entry to CHANGELOG.md with this PR
• If I added new functionality, I added tests covering it.
• If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.
• I checked whether I should update the docs and did so by submitting a PR to https://github.com/blockscout/docs
• If I added/changed/removed ENV var, I submitted a PR to https://github.com/blockscout/docs to update the list of env vars at https://github.com/blockscout/docs/blob/master/for-developers/information-and-settings/env-variables.md and I updated the version to master in the Version column. Changes will be reflected in this table: https://docs.blockscout.com/for-developers/information-and-settings/env-variables.
• If I add new indices into DB, I checked, that they are not redundant with PGHero or other tools