feature: add support for secondary nav on EDU Collections template

[stephiescastle]

Checklist

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Description

Addresses feedback:

• https://github.com/nasa-jpl/www/issues/617

Changes

• Adds support for secondary nav on the EDU Collections template
• Adds additional stories to demonstrate the use-case with different hero configurations

Note: the following needs to be completed for the secondary nav to be used in the CMS

• https://github.com/nasa-jpl/www/issues/616

Instructions to test

1. make vue-storybook
2. View stories that pair secondary nav with:
   • Hero: http://localhost:6006/?path=/story/templates-edu-pageeducollectionsdetail--secondary-nav&globals=theme:ThemeEdu
   • Inline hero: http://localhost:6006/?path=/story/templates-edu-pageeducollectionsdetail--secondary-nav-hero-inline&globals=theme:ThemeEdu
   • No hero: http://localhost:6006/?path=/story/templates-edu-pageeducollectionsdetail--secondary-nav-no-hero&globals=theme:ThemeEdu

Tested in the following environments/browsers:

Operating System

• macOS
• iOS
• iPadOS
• Windows

Browser

• Chrome
• Firefox ESR
• Firefox
• Safari
• Edge

[stephiescastle]

Note that https://github.com/nasa-jpl/www/issues/616 will need to be completed for the secondary nav to actually be used in the CMS