detect !inner in one-to-one relationships

[wyozi]

What kind of change does this PR introduce?

Select query type parser feature/bugfix

What is the current behavior?

.select("a_onetoone_rel!inner(*)")

results in a nullable a_onetoone_rel, while it should be non-nullable due to !inner

What is the new behavior?

Detects this case and removes nullability of the inner one-to-one relationship.

Additional context

non one-to-one case was fixed in #458

[wyozi]

@steve-chavez this would be good to have merged, since otherwise #458 will behave very unexpectedly with !inner randomly not working on one-on-one relationships