Covid series landing page

[joshdarby]

Changes

This pull request makes the following changes:

• Adds a new series landing page template named Series Landing Page Parent/Child. The only difference between this landing page and the default landing page template is that this new template does not show the default series posts river and the order of header elements is rearranged.
• Adds styling for both landing page templates for the header and Largo Recent Posts widgets shown on the templates

Desktop (new template):

Mobile (new template):

Default (old template):

Series landing page settings:

Why

For #

Testing/Questions

Features that this PR affects:

• Series landing pages

Questions that need to be answered before merging:

• Is this PR targeting the correct branch in this repository?

Steps to test this PR:

1. View it and make sure it looks ok