feature: EDU Event Detail Page

[stephiescastle]

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Description

Supports https://github.com/nasa-jpl/www/issues/141

• Adds PageEduEventDetail template component
• Fixes CalendarButton component
• Adds a "dark mode" for BlockLinkCard, which is used in the "Explore More" section at the bottom of the page
• Card styles are not complete -- they are part of a separate issue: https://github.com/nasa-jpl/www/issues/191

Instructions to test

1. make vue-storybook
2. view http://localhost:6006/?path=/story/templates-edu-pageedueventdetail--base-story&globals=theme:ThemeEdu

Tested in the following environments/browsers:

Operating System

• macOS
• iOS
• iPadOS
• Windows

Browser

• Chrome
• Firefox ESR
• Firefox
• Safari
• Edge

[stephiescastle]

Noting that the Percy snapshots are nearly useless as some will fail and then succeed, making the diff unusable. Attempting to fix that here. If I can't, I'll create a new issue and work on it separately.

[stephiescastle]

Did not solve the percy issue in this PR. I've opened an issue with the percy-storybook team: percy/percy-storybook#1008