to add eosio.md

[bumblefudge]

paging @sebastianmontero -- I took a lot of liberties updated and rephrasing your work, please DM me on the CASA discord if you'd like to discuss! In particular, let me know if there's anyone in the EOSIO community I should be asking for help. I noticed googling around that LACChain is using EOSIO, it would be great to get their chain_id into the examples 😄 🇦🇷

OPEN QUESTIONS:

1.) are the examples I manually composed accurate in the CAIP-10 section?

2.) should there be a CAIP-19/20/21 NFT section, or is the NFT development environment of EOSIO too young/unstandardized? I saw this in the docs and didn't have time to dig into how interoperable they are with one another, or with the EIPs governing NFTs...

3.) similarly, I didn't have time to look into whether the node-APIs support JSON-RPC (and thus justify a CAIP-25/27 section). full disclosure: adding such a section is definitely above my paygrade and availability, but happy to help edit it if someone else can!