Modularize Solidity contracts for upgradeability & extensibility

[sisyphusSmiling]

Closes: #66

Description

To enhance the extensibility and modularity of the EVM contract, this PR refactors the EVM factory contract into 3 distinct entities:

1. Deployment registry - maintains state associations between factory-deployed EVM contracts and their corresponding Cadence implementations, e.g. A.123.ExampleNFT.NFT => 0x345...789 and vice versa
2. EVM contract deployers - tasked with deploying a contract from template using the deploy interface method
3. Factory - primary entrypoint for the bridge COA which enables the deployment of new EVM-defining contracts for Cadence-native assets and utility methods to inspect EVM state.

Of these three, the registry is intended for permanent use. By decoupling state from functionality, we're able to upgrade to new factory contract version (e.g. add util methods, etc.), add new deployers (e.g. support bridging novel Cadence assets as totally new ERCs or new ERC combinations, etc.).

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For contributor use:

• Targeted PR against main branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the standards mentioned here.
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.03%. Comparing base (428634e) to head (6c4c835).
Report is 110 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #67      +/-   ##
==========================================
+ Coverage   82.88%   86.03%   +3.15%     
==========================================
  Files          18       18              
  Lines         818      888      +70     
==========================================
+ Hits          678      764      +86     
+ Misses        140      124      -16     

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[jordanschalm]

I mainly looked over the Solidity contracts. The overall organization of the contracts looks good to me. Didn't notice any implementation issues, but suggested a few documentation changes.

[ramtinms]

Looks good to me, though I have limited skills in reviewing codes in solidity.

[joshuahannan]

I didn't really review the Solidity code much but everything else looks fine

[joshuahannan]

Technically it is possible for assets to be both fungible and non-fungible tokens, right? Are we not supporting that for simplicity?

[sisyphusSmiling]

Technically it is possible for assets to be both fungible and non-fungible tokens, right?

Not without function overloading in Cadence since both have functions named deposit and `withdraw.

Are we not supporting that for simplicity?

That's right - mutually exclusive implementations are the only use cases supported for v1. That may change in the future. While it's not currently possible to have a mixed FT/NFT due to the need for function overloading, I added the check here anyway in case it does become technically possible at some point in the future.