shall use leftJoin by default and support on clause

https://github.com/nestjsx/crud/blob/35acb442c62cdebea7fd33f5c1e9cf1dec31d539/packages/crud-typeorm/src/typeorm-crud.service.ts#L335-L344

shall use leftJoin by default and use innerJoin by config see sequelize options include.required behavior

If the relation can be set NULL, innerJoin will break the query.

refer: http://docs.sequelizejs.com/class/lib/model.js~Model.html#static-method-findAll

Name	Type	Attribute	Description
options.include[].required	boolean	optional	If true, converts to an inner join, which means that the parent model will only be loaded if it has any matching children. True if include.where is set, false otherwise.

[michaelyali]

@Diluka @macchie this will have a high priority on the next release.

[Diluka]

export type QueryJoin = {
  field: string;
  select?: QueryFields;
  required?: boolean; // <-- add here?
  on?: string; // <-- maybe this together?
};

You do this PR is better. I need to take the time to familiarize myself with this new architecture.

When using left join and the relation can be set null, the same condition put in on or where can be different result.

p.s. I feel that it will become more and more complicated here.