Adding new items and standardizing dates

[JN513]

Added:

Implementations: Grande Risco-5
Tools: Risco-5S RISC-V Simulator

Correction:

I standardized the date formats in the items. Some dates were in the format year-month-day, while others were in year-day-month. Since the initial items used the latter format, I kept that as the standard. If you prefer the first format as the standard, I can easily switch the dates to it, as they are now all uniform, making the change straightforward.

One suggestion I have is to create a CONTRIBUTING file outlining all the repository's standards and contribution guidelines. Alternatively, you could expand the "Making Contributions" section of the README, though it might not be ideal for this section to become too lengthy, especially considering the README will likely grow significantly. Including just one or two sentences there with a link to the CONTRIBUTING file for detailed guidelines could be a better approach.