Create a package for Bech32 encoding of addresses

[mpizenberg]

Cardano addresses have 2 main representations. One is binary using raw bytes, the other is Bech32, an address format standardized by Bitcoin. Here is an example of the same address, in raw bytes (hex encoded) or in Bech32:

• Bech32: addr_test1vza0s44v9ljpgu5h9wkayt03s5406adkdk8xju5dcd853acuqzfzx
• Raw bytes (hex encoded): 60baf856ac2fe41472972badd22df1852afd75b66d8e69728dc34f48f7

The Bech32 format is more user-friendly because it contains a human-readable prefix, but is less convenient for actual programming stuff. So currently, we only support the raw bytes format in elm-cardano. It would be great if someone could create a Bech32 elm package, that we could reuse in elm-cardano.