feat(Masthead): Spike inline nav for masthead

[markhigham]

Related issue

Closes #3743

Overview

Create a variant of Masthead component which displays the MastheadNav inline. It is currently rendered beneath the masthead

Reason

To align the DS component with in the field implementations. To provide more vertical screen space as requested by downstream consumers.

Work carried out

[A list of work you have done, use markdown checklist format, if you leave any boxes unchecked, be sure to set this PR as a WIP]

Example.

• [x] A bit of work I completed
• [ ] A bit of work I did not complete

Screenshot

[If the work is UI related then paste a screenshot of the update here.]

Developer notes

[Sometimes, extra notes are needed to add clarity to a PR, add them here]

[netlify[bot]]

✅ Deploy Preview for storybook-navy-digital-mod-uk ready!

Name	Link
🔨 Latest commit	a4ae5be554253f9354169a6b4e12387f49a87f60
🔍 Latest deploy log	https://app.netlify.com/sites/storybook-navy-digital-mod-uk/deploys/66180ac031a32d0008b9e30e
😎 Deploy Preview	https://deploy-preview-3744--storybook-navy-digital-mod-uk.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[markhigham]

Change margin for banner to padding so that bottom border extends the full screen width. Change to prop name from inlineNav to hasInlineNav

[sonarqubecloud[bot]]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud