WETH wrapper logic methods

• All methods can only be called by the vault owner.

• wrapNative: Deposits native network currency sent in an external call to weth.

• wrapNativeFromVaultBalance: Deposits native network currency located on the vault contract into weth. Throws WETHwrapper_InsufficientBalance error if amount > address(vault).balance.

• unwrapNative: Converts weth located on the vault address to native network currency. Throws WETHwrapper_InsufficientBalance error if there are insufficient weth tokens on the vault contract. The converted balance remains on the vault address.