Epic: Fix up all FKs and related names to follow a self-consistent pattern

Proposed Changes

We don’t have a single consistent pattern for foreign key names and (especially) related names on the corresponding reverse relations, for example:

• Site.powerpanel_set versus Site.rack_groups (pluralization, underscores)
• PowerFeed.power_panel versus PowerPanel.powerfeeds (underscores)
• Tenant.rackreservations versus Tenant.route_targets (underscores)

etc.

Fixing this will be a breaking change for the ORM and possibly also for the REST API and/or GraphQL as well, but it’s the right thing to do long-term.

Justification

Tech debt reduction, improved self-consistency and ease of use.

TODO

• #2960
• Do the work (to be updated upon completion of spike)

[jathanism]

My proposal as we had discussed before is to use the Meta.verbose_name_plural for the related model and normalize spaces to underscores. For example:

In [1]: RackReservation._meta.verbose_name_plural
Out[1]: 'rack reservations'

In [2]: from nautobot.utilities.utils import slugify_dashes_to_underscores

In [3]: slugify_dashes_to_underscores(RackReservation._meta.verbose_name_plural)
Out[3]: 'rack_reservations''

… and so on.

To me this gives us determinism and consistency and makes it easy to write lint checks if we want to do so.

The only edge cases would be for m2m such as specifying a best practice for when we do not want a related name (e.g. using related_name="+") or where we want an interpolated related name (e.g. related_name="foo_%(model)s_related").

[gsnider2195]

As part of this can we standardize on parent/child relation names for tree objects? django-tree-queries doesn’t give you an option to choose the names for those relationships so anything that’s a django-tree-queries TreeNode is already using parent/children but we have inconsistencies on MPTTModels. For example InventoryItem uses parent/child_items and Region uses parent/children.