Notional fCash as collateral

[alcueca]

• Regular Join that takes ERC1155 assets, but is locked to a single id. No flash loans.
• Minimal Ladle module to transfer ERC1155 assets. No permit.
• Minimal Oracle that prices fCash at face value.

Check the README for more details.

All files have been stored in contracts/other/notional. We can have a discussion on how to organize this repo better.

1. I think that we could keep specific integration contracts in other, which would also mean moving a bunch of oracles.
2. The ERC1155.sol contract can be imported from solmate, or copied into utils.
3. The Join1155 could go into a joins folder since it is not specific to any solution.

[alcueca]

There is actually an ERC1155 wrapper for fCash

[devtooligan]

Are we fairly certain on this? Should we consider if they are hacked or something and the face value cannot be redeemed?

[devtooligan]

Overall looks good. I didn't find any dealbreakers, just some suggestions and a couple questions.

Deploy scripts will be in a different pr, right? And we will be doing some mainnet fork tests at that time I guess? Two things to track when doing the mainnet fork tests are:

1. Does the safeTransferFrom work properly when pointed to the main proxy ctrct
2. remember to do the setApproval for the ladle

I'm happy to approve this after a little more discussion on some of the questions I brought up, the actual code change suggestions are not that important to me

[alcueca]

No one of you found the brown m&m. Tsk, tsk.

[alcueca]

I'm merging this PR now, thanks for the feedback received. It remains a bit of thinking on how to reorganize the repository for continued development.