Support Native queries, parameterized views

[BenoitRanque]

v0.2.2 release

This PR adds support for (parameterized) native queries, and parameterized views.

It also includes multiple bugfixes and changes to hopefully generally improve the codebase.

• Return error if empty list of query variables passed. Variables should be ommited or be a list with at least one member
• Use table comment as description for corresponding collection and object type
• Return json representation for applicable scalar types in schema response
• Add configuration.schema.json to generated configuration directory
• Bump ndc-spec dependency to 0.1.1
• Config breaking change: use maps for tables and columns list, rather than arrays. This should help avoid duplicate alias issues
• Move parsing column data types into configuration time and startup time, instead of query execution time. This should give error feedback earlier
• Allow tables and native query return types to be marked as identical to return types for other tables/queries
• Support parameterized views (don't support column valued arguments)
• Support parameterized native queries, except in foreach queries. Also don't support column valued arguments
• Change explain output so the console knows how to extract generated SQL and sql explain plan to display to the user
• Pretty print explain SQL output
• Fix a bug where no result sets where returned when foreach predicate didn't match any rows. Correct behavior: empty result set is returned