Feat/model into mongo

[KartikGS]

Adding the models to mongodb as a part of pr#1362 and fix#1286

I have simply used the inferred modelConfig Type and added it to the database collection

Changes to hooks.server.ts same as done by @neven4

[nsarrazin]

Going to review first #1362 so we can agree on a way to do it and then will take a look at this :smile: thanks for looking at it!