feat: add contract uri and set token uri on mint to erc721

[cryptotavares]

Description

Updated erc721 token contract to:

• add a contractURI will allow OS to discover collection metadata easily.
• setting a tokenURI on mint will allow us to avoid an extra trx to set a tokenURI.

Motivation and Context

We want to have an erc721 contract that would allow us to easily have collections being available on OS (and similar platforms). In order to do that we are adding a contractURI for retrieving collection metadata (https://docs.opensea.io/docs/contract-level-metadata).

Besides that we have also decided to add the possibility to set a tokenURI on the mint function (in most cases we will already have a URI where from where the metadata for a given token can be retrieved, so we can avoid doing another trx just to set the token URI). This parameter is optional (mint should work without setting a tokenURI as well).

How Has This Been Tested?

Only using the existing unit tests.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [x] All new and existing tests passed.

[github-actions[bot]]

CLA Assistant Lite bot All contributors have signed the CLA ✍️

[cryptotavares]

I have read the CLA Document and I hereby sign the CLA