feat: add schema parsing to live collections

[ascorbic]

Changes

Adds schema parsing to live content collections.

• parses the returned data from getCollection and getEntry
• updates types so that if schema is defined, collections will be typed using that rather than the loader type
• refactors error handling and adds more checks for the config and the data

Testing

Still needs tests

Docs

Added a new error

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Latest commit: 375d854

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[ematipico]

Left few questions around the code. It would be great if the RFC would cover error handling

[ematipico]

Why the change?

[ascorbic]

When the AstroError is thrown inside the content config it's not recognising it as an instance of the AstroError class, so isn't giving the nicely-formatted error messages