fix(mc-html-template): add preload and includeSubDomains to header

[tdeekens]

Summary

This adds the preload and includeSubDomains attributes to the Strict-Transport-Security header.

Description

Using hstspreload.org it is advised to preload (not part of the spec) and add the includeSubDomains attributes. More about HTS here.

I don't see a strict reason against adding those.

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🦋 Changeset detected

Latest commit: 1879af1

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@commercetools-frontend/mc-html-template	Patch
@commercetools-frontend/mc-scripts	Patch

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[tdeekens]

I was hesitant of the includeSubDomain directive. However, I checked and all subdomains under ct.com have HTTPs enabled so there shouldn't be any issues.

[tdeekens]

Confirmed with SRE, using includeSubDomains is fine.