Incorporate postgraphile-tag-json-tools

[benjie]

Feature description

@phryneas has written https://github.com/mayflower/postgraphile-tag-json-tools which enables more accurate JSON schema for the postgraphile.tags.jsonc file, leading to better auto-complete (and hopefully detection of misconfiguration, e.g. typos in references, invalid tags, etc).

Breaking changes

Potentially more esoteric tags won't be supported.