Polygon: Add a Custom API Provider UX

[exitus1]

Currently, the wallet prompts users to add a custom API provider, however, there's no link or information as to where they can find providers. For users less intimately educated on Polygon/ETH this can be a source of confusion.

Google searching Polygon API providers doesn't yield direct results either.

My hope is the UX/UI can be improved with better/direct directions. Whatever would make sense to a novice user.