EVM Engineering: propose moving dispute/cannon contracts to appropriate folders

[smartcontracts]

Contracts within the dispute and cannon folders are L1 contracts but live in distinct folders for no clear reason. I propose that we should consider one of two things:

1. We move these contracts into the L1 folder just like any other contract
2. We add some new subfolders to the L1 folder to organize things like L1/cannon, L1/dispute, L1/bridge, L1/core etc etc

Tasks here:

• Open a design doc with both of these options presented (also third option, don't move the contracts)
• Figure out what to do
• If we make a decision, execute on it

[K-Ho]

Flagging context from Kelvin that "this technically does change the contract source code because the import paths will change, so it does need to be included in an upgrade"