* ctb: Naming and comments to clarify interfaces usage

The OptimismMintableERC20 token used two interfaces in its
supportsInterface() function. These were confusingly named
after the functions that they contain (ie. IL1Token, IRemoteToken),
rather than the contracts these interfaces represent.
The name has been tweaked slighly, and comments have been added to
clarify the intent.

fix(ctb): Clearer names for the mintable token iface

* ctb: Add bridge() to mintable erc20 interface

* chore: bindings