Add support for partially verified via sourcify contracts

[nikitosing]

Closes #4317

Changelog

• If smart-contract verified via Sourcify Blockscout will fetch it automatically
• Added support for partially verified contracts via Sourcify

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

[mj5599-spo]

[vbaranov]

Some nitpicks about the naming and method interface changing, test coverage in the code and:

1. Incorrect URL generated to Sourcify repository for partially verified contract: https://repo.sourcify.dev/contracts/full_match/partial_match/77/0xE300553919bEC8641eF110cbc9042b83b9f4b5a1/
2. I know this is not a part of concrete this PR, but let's put "Verify & Publish" button above:
   

[vbaranov]

listcontracts API endpoint with unverified option returns verified in Sourcify contracts. It should return them with verified option.

[vbaranov]

listcontracts API endpoint with unverified option returns verified in Sourcify contracts. It should return them with verified option.

This works in fact