Add dexscreener actions

[elegant651]

🚀 The feature, motivation and pitch

As part of ETH Global Agentic Ethereum, we created an action provider to get the dexscreener data. It would be very useful to have token information that can be fetched from the dex.

Actions include:

• Get pairs by chainId and pairId from Dexscreener
• Get all token pairs for given token addresses from Dexscreener
• Search for pairs matching a query string on Dexscreener

completed unit testing as well as e2e testing.

Alternatives

No response

Additional context

Link to fork : https://github.com/elegant651/agentkit/tree/feat/dex-screener
Link to showcase: https://ethglobal.com/showcase/undefined-vj2oq