Add Uniswap V3 BNB to ecorouter

[0xVenky]

Tasks

• Update Swapr SDK to handle BSC in Uniswap router v3
• Update Swapr Dapp to use the new SwaprSDK and Uniswap Smart Order router

[wixzi]

BSC is added to the latest release of https://github.com/Uniswap/smart-order-router so will take up this task again

[wixzi]

I need some help with Swapr SDK to get it working. So parking for now.