Add metadata views for Fungible Token contracts

[joshuahannan]

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Issue To Be Solved

The metadata standard that we are currently using for NFTs can also be utilized for fungible tokens We should create views and add them to the FT standard.

Suggest A Solution

• Should the views go in the regular MetadataViews contract in the NFT repo or create a new contract?
• Can we re-use existing views, or does it not make sense to get them mixed up?
• Need to define a display view, a path information view, a license view, externalURL, any more?
• Add the views to the ExampleToken contract and tests
• Create docs/tutorials for how to use them and migrate