Update brand guidelines references

[janbrasna]

Description

With mozilla.design being completely outdated, these could use a new destination:

bedrock/bedrock/mozorg/redirects.py

Lines 479 to 482 in 6d4fa5c

	redirect(r"^styleguide/products/firefox(.+)", "https://mozilla.design/firefox/"),
	redirect(r"^styleguide/identity/firefox(.+)", "https://mozilla.design/firefox/"),
	redirect(r"^styleguide/identity/mozilla(.+)", "https://mozilla.design/mozilla/"),
	redirect(r"^styleguide(/.*)?", "https://mozilla.design/"),

The brand portal currently provides this public endpoint:

• https://brand.mozilla.com/public
  that can use some better visibility.

Also a new refract has been added for:

• http://brand.firefox.com
  expecting this hub to also get public eventually.

I'll verify the destinations and timelines, and update these accordingly.

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Success Criteria

• Redirects updated to frontify URLs
• All direct links to mozilla.design also updated or replaced