Prepare tests for supporting QUERY method.

Include QUERY method when fetch collection permission is granted for a
resource.

Include string matching operators.

Use key-value to ensure less duplicates in coercing query param values.

Remove directives, stick to simple querying via equality.

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.