Improvement news item time filtering

[StefC93]

Assess --> News Items

Change the time filters from "Today", "This week", "This month" to "Last 24 hours", "Last 7 days", "Last 31 days".

This makes it easier for an analyst that's reviewing the items on a daily basis. Currently, an analyst would need to use "This week" to check items that were ingested after work hours (18:00-midnight). This also counts for an analyst that starts working on Monday, after the weekend. The analyst would then need to use the "This month" filter to see the ingested items from Friday 18:00 until Sunday 23:59.

Possibly an additional "Last 3 days" filter could be implemented to cover ingested items during the weekend.