[docs]: add gelato vrf

[anirudhmakhana]

Description

This pull request introduces Gelato VRF (Verifiable Random Function) to our suite of tools, enhancing the capabilities of smart contract developers on Optimism. Gelato VRF enables secure and transparent generation of verifiable randomness on-chain, empowering various applications such as gaming, DeFi, and more.

Additional context

With the addition of Gelato VRF, developers gain access to a reliable source of randomness for their smart contract applications, fostering trust and integrity within the Optimism ecosystem. This enhancement aligns with our commitment to providing comprehensive solutions for decentralized development.