feat(mongo): allow using different primary key types than ObjectId

[ayazhussein]

Closes #349

[ayazhussein]

What do you propose?

[B4nan]

Correct fix is to handle this based on the metadata. If the property type is not object id, we dont want to convert it.

It will be much more complex change, I don't know what and where, if I knew, it would be already implemented... But changing the platform methods is wrong I think, we should instead make sure they are not called for properties with non object id type. Also we need tests for the actual issue, where the PK is string, but it is 24 char hex string that can be converted to object id without problem (that is what #349 is about). We also need tests with numeric PK (as numbers can be also converted to object id without problems).

[B4nan]

I already did some changes in this manner here: 86cd027

[ayazhussein]

it doesn't cover all the cases, I did some changes, let me know if they are better

[B4nan]

Good, much better! Will need more time to review it properly, but this looks like the correct way to me.

[B4nan]

ok this looks good, please fix those few code style changes i asked for and i think we are good to merge.

or do you think there are some uncovered edge cases? i would maybe suggest adding one more test that will be about numeric PK, but the code should handle this case properly, so it should be just about adding the test case to be sure.

[B4nan]

Good, thanks again!