Rename CustomField `object_type` to `related_object_type`

[jeremystretch]

NetBox version

v3.7.3

Feature type

Change to existing functionality

Proposed functionality

Rename the object_type ForeignKey field on CustomField to related_object_type (or any better suggestion).

Use case

Following the renaming of the content_types ManyToManyField to object_types under #15277, the name object_type can now be quite confusing. (object_types defines the types of NetBox objects on which the field appears, whereas object_type indicates the model indicated by an object or multi-object field.) Renaming this field should help avoid user confusion.

Database changes

Rename the object_type ForeignKey field on the CustomField model (effecting a migration).

External dependencies

None