Allow unwrapping v5 and v6 and allow wrapping v8 via nothingtoken.com

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We should make this possible through the site. I have put an option in the design where we could put this on the site, this would require people to connect with the web extension.

Mind the post conditions when implementing this.

Some example of wrapping MNO to Wrapped MNO v8
https://explorer.stacks.co/txid/0x3a498af27cd2a839a4cf2f6bac727b87f65b619b364b2d01faf71c01f65799eb?chain=mainnet

Some example of unwrapping v5
https://explorer.stacks.co/txid/0x77603ae3f6157f6e6f9f18b08c18583b712dfb9bedc9640c82657453be3c96a0?chain=mainnet

Some example of unwrapping v6
https://explorer.stacks.co/txid/0x4e6cdf5a39143e104e7124346986c55abcb2b5dc8fdb244f5602a27ebaf4fdc2?chain=mainnet

By the way v7 was never handed out via the faucet.