Restructure and add nft-chain-keys

[PiVortex]

Closes #28
Part of near/docs#2011

• Restructured repo to include multiple examples
• Implement example of sending transactions through NFT Chain Keys for Ethereum and minting new NFTs (works for web wallet and extension wallet)

[PiVortex]

@race-of-sloths get me in the race!

[race-of-sloths]

@PiVortex Thank you for your contribution! Your pull request is now a part of the Race of Sloths!
Weekly streak is on the road, smart strategy! Secure your streak with another PR!

Current status: executed

Reviewer	Score
@gagdiez	5

The average score is 5

@PiVortex check out your results on the Race of Sloths Leaderboard! and in the profile

What is the Race of Sloths

Race of Sloths is a friendly competition where you can participate in challenges and compete with other open-source contributors within your normal workflow

For contributors:

• Tag @race-of-sloths inside your pull requests
• Wait for the maintainer to review and score your pull request
• Check out your position in the Leaderboard
• Keep weekly and monthly streaks to reach higher positions
• Boast your contributions with a dynamic picture of your Profile

For maintainers:

• Score pull requests that participate in the Race of Sloths
• Engage contributors with fair scoring and fast responses so they keep their streaks
• Promote the Race to the point where the Race starts promoting you
• Grow the community of your contributors

Feel free to check our website for additional details!

Bot commands

• For contributors
  • Include a PR: @race-of-sloths include to enter the Race with your PR
• For maintainers:
  • Assign points: @race-of-sloths score [1/2/3/5/8/13] to award points based on your assessment.
  • Reject this PR: @race-of-sloths exclude to send this PR back to the drawing board.
  • Exclude repo: @race-of-sloths pause to stop bot activity in this repo until @race-of-sloths unpause command is called

[bh2smith]

This looks great, but it seems a bit outdated now given the recent release notes

https://github.com/near/mpc/blob/develop/CHANGELOG.md

I am still struggling to get the deriveChildPublicKey to align in BitteProtocol/near-ca#65

[gagdiez]

@race-of-sloths score 5

[gagdiez]

will merge this and add the new interface in the merged version

[race-of-sloths]

🌟 Score recorded!

@gagdiez, thank you for scoring this pull request in the Race of Sloths!

[race-of-sloths]

✅ PR is finalized!

Your contribution is much appreciated with a final score of 5!
You have received 65 (50 base + 15 weekly bonus) Sloth points for this contribution

Another weekly streak completed, well done @PiVortex! To keep your weekly streak and get another bonus make pull request next week! Looking forward to see you in race-of-sloths