Refactor configs and tidy them up with Zod validation

[ViorelMocanu]

Example: https://github.com/nemanjam/nemanjam.github.io/blob/main/src/config/client.ts Another example: https://github.com/superwebthemes/barebones/blob/main/src/types.ts + https://github.com/superwebthemes/barebones/blob/main/src/siteConfig.ts