Ref #197

This PR adds in 3 new criteria method for JSON::Any columns

• has_key which performs WHERE jsonb ? 'some_key'.
• has_any_keys which performs WHERE jsonb ?| '{"this_key", "or_that_key"}'
• has_all_keys which performs WHERE jsonb ?& '{"this_key", "and_this_key"}'

This makes doing queries on JSON columns a little easier since you can't do raw WHERE queries on these because they use the ? character which the PG shard uses as a placeholder ref

class User < BaseModel
  table do
    column preferences : JSON::Any
  end
end

UserQuery.new.preferences.has_key("theme")
UserQuery.new.preferences.has_any_keys(["theme", "color_mode"])
UserQuery.new.preferences.has_all_keys(["theme", "style"])

Side note: I'm not having this PR close the issue because I want to add 2 more in a separate PR to perform @> and <@