Add automatic news for new records (e.g. sites, personal)

[KaiWissel]

If a flight exceeds a certain threshold (FAI:10, FLAT:15, FREE: 20k) and is a new record for this site or person at a automatically a news on the Landing Page.

• Should we do only for one, both or neither?
• What about the thresholds?
• Display for one week?
• At a flag to other news with "always on top"; Because only three entries will be shown on landing page

Implementation details:

• Store calculated results in a cache and check the results of a new flight against this cache and replace data if necessary.
• Calculated inital values on every server start up
• This would also reduce the response time of user requests to SiteRecord and UserList

[KaiWissel]

• Should we do only for one, both or neither? --> sites
• What about the thresholds? --> okay
• Display for one week? --> okay

And inform admins via mail

[KaiWissel]

Use this as a starting point https://github.com/XCCup/xccup.net/pull/650