Add link to record support to belongs to field

[krystof-k]

Description

This adds support for link_to_record to belongs_to field, meaning on index view it will link to the record instead of the associated record.

Closes already closed #2689.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

Screenshots & recording

Manual review steps

1. Step 1
2. Step 2

Manual reviewer: please leave a comment with output from the test if that's the case.

[codeclimate]

Code Climate has analyzed commit 4fa11d1 and detected 1 issue on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	1

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[krystof-k]

I have no idea why the test is failing but it should work… I will update the docs when this is merged.

[krystof-k]

Yeah, of course it is failing because it has the link to enabled… I'll try to fix it.

[Paul-Bob]

Thanks for looking into this @krystof-k the PR looks good!