MWPW-155317: [CaaS] add support for link rewriting

[sanrai]

This PR adds support for link transformation in the CaaS (Content as a Service) component. It allows consuming projects to define a custom link transformer function that will be applied to links within the CaaS content.

This feature enables projects to dynamically transform links in CaaS content, which can be useful for staging environments, A/B testing, or other scenarios where URL modification is required.

Changes:

• Add logic to pass the caasLinkTransformer function from the page config to the CaaS component configuration
• Update the getConfig function to include the link transformer if defined

// In the consuming project's configuration
const config = {
  ...
  caasLinkTransformer: { } // settings defined inside here
};

Resolves: MWPW-155317

Test URLs:

• Before: https://main--milo--adobecom.hlx.page/drafts/sanrai/foo?martech=off
• After: https://MWPW-155317--milo--adobecom.hlx.page/drafts/sanrai/foo?martech=off

[github-actions]

Reminder to set the Ready for Stage label - to queue this to get merged to stage & production.