Added Fresh Relevance module

[dhendo]

Related Issues

Implements #4259

Short Description and Why It's Useful

Add support for Fresh Relevance script injection and data collection using existing hooks.

Screenshots of Visual Changes before/after (if There Are Any)

n/a

Which Environment This Relates To

• Test version (https://test.storefrontcloud.io) - this is a new feature or improvement for Vue Storefront. I've created branch from develop branch and want to merge it back to develop
• RC version (https://next.storefrontcloud.io) - this is a stabilisation fix for Release Candidate of Vue Storefront. I've created branch from release branch and want to merge it back to release
• Stable version (https://demo.storefrontcloud.io) - this is an important fix for current stable version. I've created branch from hotfix or master branch and want to merge it back to hotfix

Upgrade Notes and Changelog

• No upgrade steps required (100% backward compatibility and no breaking changes)
• I've updated the Upgrade notes and Changelog on how to port existing Vue Storefront sites with this new feature

IMPORTANT NOTICE - Remember to update CHANGELOG.md with description of your change

Contribution and Currently Important Rules Acceptance

• I read and followed contribution rules

[gibkigonzo]

Thanks :) Can you please extract it to separate module (repo) and add info here about this integration https://github.com/DivanteLtd/vue-storefront/tree/master/docs/guide/integrations ?

[dhendo]

Thanks, pulled out into separate module.

[dhendo]

Updated integrations docs as requested, in #4475