Add parsing for query directives.

Define function for decoding query params into native query collections.

Include sequences in data source definition.

Put message key in its correct location.

Unify returning of Accept-Post and Accept-Patch items.

Include basic description of the error and the steps to resolve them.

Include example project and requests.

Tidy up some parts of the codebase.

Put data source to its own package.

Prepare project for multiple packages.