Create Total Submissions stats component

[stepchud]

What/Why

The stats section at the top of the submission list view. These stats could be expensive to query so let's consider performance implications while designing this.

[Story]

Figma Link

[stats section](The stats section at the top could be expensive to query and we may want to cache this component since it doesn't change that frequently and slightly out of date stats are okay.)

Acceptance Criteria

• uses USWDS Summary box component, perhaps?

Disregard the following if this work does not include any UI changes

• WAVE screenshot
• Automated a11y tests (axe-rspec specs)
• Keyboard accessibility (tab navigation, form interactions)
• Responsiveness at desktop and mobile