This commit adds two things:
a section on the dashboard to show how many inbound messages the
service has received in the last 7 days, and how recently an inbound
message has been received
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Doesn’t show the contents of any messages, just like how the rest of the
dashboard is an aggregation, never individual messages.
a page to show all the inbound messages the service has received in
the last 7 days
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This shows the first line of the message. Eventually this will link
through to a ‘conversation’ page, where a service can see all the
messages it’s received from a given phone number.
