cis2-dynamic-nft example contract

[bogacyigitbasi]

Purpose

cis2-dynamic-nft smart contract is a derivative of cis2-multi that allows multiple metadata URLs in a vector for a token. A new metadata URL can be pushed to the vector, and the token can be upgraded. An upgrade means the metadata index is increased by one, and the function tokenMetadata returns only the last element in the vector, and the whole history of metadata URLs is visible with another function called tokenMetadataList. A real life (!) example of a dynamic NFT could be the evolution of a Pokemon or a game character. OR a service book history for a car.

Changes

_Describe the changes that were needed.

Checklist

• My code follows the style of this project.
• The code compiles without warnings.
• I have performed a self-review of the changes.
• I have documented my code, in particular the intent of the
  hard-to-understand areas.
• (If necessary) I have updated the CHANGELOG.

CLA acceptance

_Remove if not applicable.

By submitting the contribution I accept the terms and conditions of the
Contributor License Agreement v1.0

• link: https://developers.concordium.com/CLAs/Contributor-License-Agreement-v1.0.pdf

• I accept the above linked CLA.

[DOBEN]

Looks good now. Let's try to resolve the last comments and get the CI pipeline to run.

There is a merge conflict in the Read.me file. Please resolve (e.g. rebase your PR on top of the most up-to-date main branch).

[DOBEN]

A few minor comments and we need to get the CI pipeline to run (fix some clippy warnings). We are not far away from having this PR ready.