Create Dark Mode Screenshots for all existing screenshots

[smk4664]

Environment

• Nautobot version: N/A
• nautobot-secrets-providers version: N/A

Proposed Functionality

MKDocs Material supports providing the tag #only-light and #only-dark on images. We should add dark images where they are not already present. See

nautobot-app-secrets-providers/docs/admin/providers/hashicorp_setup.md

Lines 60 to 61 in ec614b3

	
	

for an example.

Use Case

When browsing the docs in Dark Mode, we are not blinded by the white screenshots.