Multi VRGDA via Libraries & Structs

[saucepoint]

Closes #12

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Creation & usage of multiple VRGDAs occur via structs and libraries.

This offers wonderful ergonomics because the structs and libraries hide all of parameters & math that power the VRGDAs:

    using LinearVRGDALib for LinearVRGDAx;
    using LogisticVRGDALib for LogisticVRGDAx;

    // define 2 VRGDAs to price the resources
    LinearVRGDAx internal linearAuction = LinearVRGDALib.createLinearVRGDA(1e18, 0.2e18, 1e18);
    LogisticVRGDAx internal logAuction = LogisticVRGDALib.createLogisticVRGDA(1e18, 0.2e18, 1000e18, 1000e18);

    // purchase resources according to VRGDAs
    function buyResources(uint256 amountA, uint256 amountB) public payable {
        int256 timeSinceStart = toWadUnsafe(block.timestamp - startTime);

        // use linear VRGDA to price resource A
        uint256 pricePerA = linearAuction.getVRGDAPrice(timeSinceStart, resourceASold);

        // use logistic VRGDA to price resource B
        uint256 pricePerB = logAuction.getVRGDAPrice(timeSinceStart, resourceBSold);

        ....
    }

Yep! We can have two independent VRGDAs, that rely on different function families, all in the same contract 🤓

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• Support Multiple VRGDAs in a single contract
• Example implementation (MultiNFT.sol)
• Preliminary tests
• Library + Struct-based LinearVRGDA
• Library + Struct-based LogisticVRGDA
• Library + Struct-based LogisticToLinearVRGDA
• Testing of the new implementation against existing tests

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Tangentially relevant gif

[transmissions11]

really appreciate the PR!

agree there needs to be some changes on the devex of hooking up to multiple VRGDAs.

i'm not sure a stateful solution like this is the way to go about it tho, i was more thinking of just abstracting things out into a lib (effectively like how we did it in Monaco)

#12

[saucepoint]

i see -- will stare at the code a bit more and play around to see how multiple VRGDAs could interact with a lib

[saucepoint]

Letting this marinate a bit, my fork feels a little too opinionated. Gonna close the PR and will likely just maintain a repo for multi VRGDAs