Add minor copy changes to tool body

[rmeritz]

• Rename "unassigned" to "Ready to Deliver Restaurants"
• Add overarching text on the hospitals side "Recipients" (above name, time, fulfillment)
• Add label "Amount" above the amount column

Closes: https://github.com/bocoup/blocks-capacity-planner/issues/40

The other changes requested in the issue are handled in other PRs.

[rmeritz]

Looks reasonable to me.