Support for nested links

[bhunjadi]

Support for nested links in nested objects and arrays:

Coll.addLinks({
  'meta.project': {
    collection: Projects,
    type: 'one',
    field: 'meta.projectId',
  },
})

[bhunjadi]

@StorytellerCZ

This is another PR from my repo that I didn't submit here before. I'll try to add basically everything from my fork to PRs here to have them more in sync (or ideally I'd just abandon my fork).

It's in draft because it's best to merge #403 first and then I'll make additional changes here.

[StorytellerCZ]

#403 was merged.

[bhunjadi]

@StorytellerCZ This should be ready for a review now.

[StorytellerCZ]

Only thing that I can pick up is an optional use of Array.isArray over _.isArray

[bhunjadi]

@StorytellerCZ Fixed in the latest commit

[StorytellerCZ]

Will be published in v1.5