Copy Header Widget area to mobile menu; remove "Hire Us" section from homepage

[benlk]

Changes

This pull request makes the following changes:

• Duplicates the "Header Widget" widget area into the end of the sticky nav, for https://github.com/INN/umbrella-inndev/issues/168
• Removes the "Hire us" section from the homepage, for https://github.com/INN/umbrella-inndev/issues/169

Here's the current Header Widget setup in the menu:

Left: the homepage without the "Hire Us" block

Why

Resolves https://github.com/INN/umbrella-inndev/issues/169 and resolves https://github.com/INN/umbrella-inndev/issues/168

Testing/Questions

Features that this PR affects:

• Homepage
• Menu on mobile devices

Questions that need to be answered before merging:

• [ ] Is this PR targeting the correct branch in this repository?
• [x] Is this deployed to staging?
• [ ] Are we worried about soemthing that is not a text widget with an a.btn showing up in the "Header Widget" widget area?

Steps to test this PR:

1. View the homepage to make sure that the "Hire us" section is gone.
2. On a narrow viewport where the sticky menu appears with the mobile hamburger menu, open it and scroll to the bottom to see the appearance of widgets in the "Header Widget" area. It's presently styled with the assumption that whatever shows up there is a text widget with buttons, or similar.

[benlk]

:deployed: to staging for review: https://inndev.staging.wpengine.com/

[benlk]

Approved at https://innorg.slack.com/archives/G0DSPDQ00/p1596132405000600