Use two Avalanche features

Our site is almost identical to Avalanche, and others, but they have two very nice features that we should implement:

1. When someone tries to connect Metamask for the first time and they dont have C-chain setup, their sites asks to do it automaticaly by a popup. We should do the same so new users dont need to set up EWC manually.
2. When you connect your wallet and you are on other net as ETH or BSC there is a popup offering you to change it automaticaly.

So two small changes to make Carbonswap easier to use, especially for new users.