Support proxy contracts / ability to execute view functions on verified contracts

I was trying to view the source of a contract, but his contract uses the EIP-1967 proxy pattern, so I couldn't view the underlying logic.

There are two potential features I can think of to enable viewing of the underlying logic (which is why this issue covers two feature requests):

1. Natively support proxy contracts, with a separate option on hover to view the source underlying implementation. Not sure how big the scope is here since there's at least EIP-1967 and EIP-1167, and possibly others
2. Allow view functions to be called and if the result is an address, allow it to be actionable

Start by reviewing the extension's hover behavior and any existing contract view-function interaction entry points. Clarify whether the goal is EIP-1967/EIP-1167 implementation lookup, actionable address results, or both; done should be defined as a verified contract's underlying source or returned address becoming accessible through the extension.

Written by the indexing model from the issue text.