Add Prettier and ESLint

Hi folks,

Thanks to PRs #223 and #222 by @massi-ang we have added Prettier and ESLint to ChainForge's main branch.

prettier and eslint are now run upon npm run build, and you are encouraged to run them before suggesting any PRs onto the ChainForge main branch.

We know this is somewhat annoying to anyone building on top of ChainForge, because it may make rebasing on top of latest main changes a chore. This includes myself---the changes in multi-eval branch, which I have been working on for a while now, are even harder to merge. However, the addition of consistent formatting and linting provides better standards for developer contributions, beyond the ad-hoc approach to writing code we had before.

Recently, I have had less time for code hygiene tasks for this project. However, I think converting the entire front-end code to TypeScript is the next step. This would provide more guarantees on dev contributions, may catch existing bugs, and allows us to have a standardized ResponseObject format across ChainForge that is enforced and extendable. The latter:

• would provide guarantees on format for people adding their own widgets, about what type of responses are
• would be easily extensible to additional data formats like images as input for GPT4-Vision, or images as responses for DALL-E

Additionally, I envision:

• Better encapsulation of how responses are displayed in Inspectors, i.e. a dedicated React component like ResponseBox that can then be extended to handle image outputs, if present.
• Better storage for internal responses (i.e. the one with “query”) that minimizes repeated info for LLM settings. Duplicate info in LLM settings is inflating the size of files fast. LLM at particular settings should be uids to a lookup table.
• Better / updated example flows, e.g. comparing prompts, testing JSON format, multiple evaluations
• Dev docs for how to create a new node

It doesn't seem like LLMs are going anywhere, and evaluating their output quality still suffers from the same issues. If we work together, we can make ChainForge a go-to graphical interface for "testing stuff out" ---rapid prototyping of prompt and chain ideas and rapid testing of LLM behavior, beyond ad-hoc chatting, CLIs or having to type code.

ChainForge is based on transparency and complete control. We always intend to show the prompts to developers. Developers should have access to the exact settings used for the model, too. If ChainForge adds, say, prompt optimization, it will be important to always show the prompts.

Let us know what you think of these changes, or what you'd like to see in the future. If you are a developer, please consider contributing! :)