Add Contracts Wizard for Cairo

[ericglau]

Adds Contracts Wizard for Cairo to the Templates category.

Contracts Wizard for Cairo is an interface to interactively build a smart contract out of components from OpenZeppelin Contracts for Cairo. Select the kind of contract that you want, set your parameters and desired features, and the Wizard will generate all of the code necessary. The resulting code is ready to be compiled and deployed, or it can serve as a starting point and customized further with application specific logic.

Checklist

• [x] The URL is not already present in the list (check with CTRL/CMD+F in the raw markdown file).
• [x] Each description starts with an uppercase character and ends with a period.
  Example: cairo - The Cairo programming language.
• [x] Drop all A / An prefixes at the start of the description.
• [x] Avoid using the word StarkNet in the description.

[ericglau]

The build failure is not related to this PR.

@gakonst Could you please review this PR? Thanks