Add upcoming deployment column to environments page

What does this MR do?

Adds a new column - Upcoming deployment - to the Environments page.

When there is an upcoming deployment, this column shows the build number, author, and status icon. If there is no upcoming deployment, this column is empty.

In the mobile interface, the Upcoming deployment row is only shown if there is an upcoming deployment; otherwise, it is hidden.

The column title renders as Upcoming on large screens and Upcoming deployment on small screens.

Screenshots

	Before	After
Large screens
Medium screens
Small screens
Status icon tooltip

The "medium" size interface is quite a mess, both before and after. This will be addressed in a follow-up issue: #292009 (closed)

Related to #232494 (closed)