Problem: there's no consensus on terminology used for tokens

Context: https://github.com/crypto-org-chain/cronos/pull/45#discussion_r704481008

We need to settle down on the terminologies used for different types of tokens:

- ERC20 tokens on ethereum
- ERC20 token
- CRC20 tokens on Cronos
- CRC20 token
- cosmos native tokens on Cronos
- coin
- cosmos token
- native token
- The CRO native token on Cronos
- CRO
- gas token

Start with the terminology discussion linked from PR #45 and review the three comments on this issue for existing context. Done means the project has an agreed, documented term for each listed token type and the terminology scope is clear.

Written by the indexing model from the issue text.