Fullstack reference architecture update: Add Containers

[thomas-desmond]

Summary

Add the Containers service to the fullstack reference architecture diagram.

Also add missing links to the reference architecture by solution page

Documentation checklist

• The documentation style guide has been adhered to.

[github-actions]

This pull request requires reviews from CODEOWNERS as it changes files that match the following patterns:

Pattern	Owners
/src/assets/images/reference-architecture/	@securitypedant, @haleycode, @cloudflare/pcx-technical-writing
/src/content/docs/reference-architecture/	@securitypedant, @haleycode, @cloudflare/pcx-technical-writing

[github-actions]

Preview URL: https://d3113686.preview.developers.cloudflare.com
Preview Branch URL: https://tdesmond-full-stack-ref-arch-update.preview.developers.cloudflare.com

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/reference-architecture/diagrams/serverless/fullstack-application/	https://tdesmond-full-stack-ref-arch-update.preview.developers.cloudflare.com/reference-architecture/diagrams/serverless/fullstack-application/
https://developers.cloudflare.com/reference-architecture/by-solution/	https://tdesmond-full-stack-ref-arch-update.preview.developers.cloudflare.com/reference-architecture/by-solution/