Defining environment variable types using Zod

[sodic]

This is what T3 does, we can take a look at them for inspiration. We should explore sense and either do it or close this issue.

[Zeko369]

While we're at this, zod is broken by default in wasp since the "dev client/server" tsconfigs have strict in them while the compile ones don't so in dev i.e.

z.object({name: z.string()})

produces {name: string} in dev (becauase devs can change the tsconfig)
produces {name?: string} in production

[sodic]

Related: #1057

[infomiho]

Internal doc on the matter: https://www.notion.so/wasp-lang/RFC-Wasp-env-variables-92d3c5635391455cb0b074fe4b390af7?pvs=4

In short:

• we want to be aware of all of the variables and list them explicitly in once place
• we want to enable users to access them via config import vs. using directly process.env or similar
• we want to collect and validate them in a single place (also list them in the docs, Directus does this well: https://docs.directus.io/self-hosted/config-options.html#general)
• warn users if they are missing variables (e.g. JWT_SECRET when deploying)