feat(backend): implement eth mainnet uniswap v3 resolver

[0xpanoramix]

Description

This PR adds a new controller for the positions resource.

It adds the implementation of the first resolver, for UniswapV3 on Ethereum Mainnet, which fetches one's positions and associated extra-data.

Changes include

• Bugfix (non-breaking change that solves an issue).
• Hotfix (change that solves an urgent issue, and requires immediate attention).
• New feature (non-breaking change that adds functionality).
• Breaking change (change that is not backwards-compatible and/or changes current functionality).
• Documentation update (change added to any kind of documentation).

Checklist

• I have assigned this PR to myself.
• I have added at least 1 reviewer.
• I have added the relevant labels.
• I have updated the official documentation.
• I have added sufficient documentation in code.

Testing

• I have tested this code with the official test suite.
• I have tested this code manually.

Manual tests

I started the backend and attempted to get the positions for multiple addresses on Ethereum Mainnet.