* photo.views is required field

In the many-to-many photos/albums example - photo.views is required field

* photo.isPublished must be provided

Fixes `null value in column "isPublished" violates not-null constraint`

… prevents SQLITE_MISUSE errors (https://sqlite.org/rescode.html#misuse) originating from sqlite itself (#6975)

allow discriminator values in Single Table Inheritance
like 0, "", or `null`

fixes #3891

change generated insert query to allow inserting an array of objects to oracle

fixes: #2434

This makes the `migration:generate` cli command exit with code 1 if no changes were found between the database and the schema from the code.

* test: added failing test for github issue #6948

* fix: findRoots should get the actual primary key column, fixes #6948

…tion in FindOptions (#6996)

* added new decorators

* added hooks to etnity subscriber interface

* added test code in one query runner

* removed new decorators and implemented in subscriber instead

* added "transaction" option to FindOneOptions

* added event listeners in query runners;
added test for event listeners;
updated docs;

* working on test;

* working on test;

* added test for `transaction` option;

* fixing failing test

* fixing failing test

* fixing typos

* fixing test I broke

Co-authored-by: Dmitry Zotov <dmzt08@gmail.com>