Improve responsive layouts

[emma-sg]

Browsertrix Cloud Version

v1.8.0-beta.2-3aebf2e

What did you expect to happen? What happened instead?

There are a couple of different list views in the dashboard (crawling and archived items), and they should be usable at viewport sizes below 960px.

Above 960:

Below:

Step-by-step reproduction instructions

1. Navigate to the Crawling or Archived Items views
2. Use a viewport smaller than 960px

Additional details

No response

[emma-sg]

Overview page also gets crunchy around ~800px: