Add NEXT Token

`{
    "name": "Connext Network",
    "symbol": "NEXT",
    "decimals": 18,
    "description": "Fast, trustless communication between blockchains & L2s.",
    "website": "https://connext.network",
    "twitter": "@Connext",
    "tokens": {
        "ethereum": {
       "address": "0xfe67a4450907459c3e1fff623aa927dd4e28c67a"
    }
  }
}`

   @connext