Restructuring prototype RFC

[sodic]

Fixes: #1426

Instructions for looking at the RFC

This PR includes (almost**) all necessary changes to run a project that follows the new structure. It also includes an example of one such project (the prototype).

Here's how I recommend you approach the RFC:

1. Read the PR's description (this text)
2. Go through the files, look at the changes, and read/reply to the comments.

** Details why almost are explained in the comments.

A reminder on the new structure

How does the new structure look like?

Wasp users write User code.

Wasp generates Generated Code. The Generated Code is split into:

1. SDK Code - This covers all the functionalities Wasp users import and use in User code (either directly or indirectly).
2. Framework Code - This covers the "shell" code. It's the code that imports and executes User code, indirectly importing and using SDK Code.
   

Here's an illustration of how the new structure looks like in the file system.

.
├── main.wasp
├── node_modules
│   ├── <other_modules>
│   └── <wasp_sdk_code>         # packages in the @wasp directory
├── .wasp/
│   └── <wasp_framework_code>
├── src
├────<user_code>
├── package.json
├── .eslintrc.json
└── tsconfig.json

Running the prototype

The prototype is a Wasp application that's organized according to the new structure and can run using an adopted version of waspc (the one in this branch).

Here's how to run it:

1. Checkout the branch.
2. Position yourself in waspc/examples/todo-typescript.
3. Run cabal run wasp-cli clean && cabal run wasp-cli start and wait for the app to start (i.e., stops outputting new text). You'll see a white screen in the browser (this is normal).
4. Ctrl+C the start command.
5. Run ./migrate from the project root directory.
6. Run cabal run wasp-cli start again
7. Open your browser and you should have a working prototype!

Changes in this PR

These are the changes that were necessary to get the prototype working.

1. A large chunk of the code has been moved from the .wasp/out/{server,client} (framework code) to various packages in the scope node_modules/@wasp/. Each package also includes whatever was necessary to make it work with Wasp.
2. As a result of the first change, most @wasp user imports now look a little different (the final form of SDK imports is still open to discussion).
3. A large chunk of the code now residing in node_modules/@wasp has been edited (i.e., not only copy-pasted) to allow for a more ergonomic organization and cleaner imports. You don't need to be aware of these changes, they'll become obvious during the implementation. Still, I commented on some of the changes for discussion purposes.
4. The compiler went through various small changes to make it all work.
5. Wasp no longer copies the user's code into .wasp/out/{server,client}. Instead, the framework code (i.e., code inside .wasp/out/{server,client}) now imports the user code directly. It does this using relative imports.
6. The waspc/examples directory now contains an extra app which acts as a prototype (waspc/examples/todo-typescript).

PR comments explore each change and decision in more detail, so let's discuss them there. If I missed something, feel free to start a new thread on the appropriate code segment.

[sodic]

Vite's dependency optimization was causing weird bugs.

Todo: describe

@infomiho knows what's up. @Martinsos take my word for it for now, I'll update the comment in a bit.

[sodic]

We will make an md file documenting the new structure.