feat(base_types): Add Wei type

[marioevz]

🗒️ Description

Adds a type called Wei which allows string parsing different combinations of fund amount strings, such as "1 ether", "100 gwei", "10**9 wei", and others.

Mostly meant to be used in command parameter parsing to allow more human-readable commands.

🔗 Related Issues

None

✅ Checklist

• All: Set appropriate labels for the changes.
• All: Considered squashing commits to improve commit history.
• All: Added an entry to CHANGELOG.md.
• All: Considered updating the online docs in the ./docs/ directory.
• Tests: All converted JSON/YML tests from ethereum/tests have been added to converted-ethereum-tests.txt.
• Tests: A PR with removal of converted JSON/YML tests from ethereum/tests have been opened.
• Tests: Included the type and version of evm t8n tool used to locally execute test cases: e.g., ref with commit hash or geth 1.13.1-stable-3f40e65.
• Tests: Ran mkdocs serve locally and verified the auto-generated docs for new tests in the Test Case Reference are correctly formatted.

[spencer-tb]

Nice! Never knew "finney" or "szabo" existed!

[danceratopz]

Really nice, few suggestions below!

Perhaps you'd prefer to make it explicit and not allow synonyms, I don't have a strong opinion 🙂 but normalizing the input unit and using match in a helper _get_multiplier() method makes sense to me.

[danceratopz]

Another test case.