Standardise Dappateer type documentation

[Tbaut]

As discussed, I believe it would be cleaner if every function of the Dappateer object was documented with JSDocs, and if we had the API.md generated automatically based on this.

This means:

• Add JSDocs for all the methods https://github.com/ChainSafe/dappeteer/blob/unstable/src/types.ts
• Use a GH action or any needed script to generate docs automatically based on this
• (optional as a nice to have) add some eslint rule to enforce JSDocs in this file.