Replace FeatureQuery with a custom manager method for ContentType

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Proposed Changes

NetBox uses the FeatureQuery class to filter ContentType querysets by support for a specific feature. For example, to retrieve the content types corresponding to all models which support the assignment of jobs:

queryset=ContentType.objects.filter(FeatureQuery('jobs').get_query())

This proposal is to move this logic to a custom manager method for ContentType, such that we could instead do:

queryset=ContentType.objects.with_feature('jobs')

In addressing #13427, PR #14152 proposes introduce a proxy model and custom manager for ContentType, which would be easily extended to support this implementation.

Justification

FeatureQuery has always felt cumbersome to use, and is not invoked consistently for all use cases (i.e. sometimes get_query() is needed and sometimes not). The proposed approach provides a much cleaner mechanism for filtering ContentTypes by supported feature.

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Blocked by #13427