Archive Alert/Warning Data

[dpaulat]

Add archive alert and warning data. Consider adding additional warning types, in addition to watches and other information as well.

Currently, https://warnings.allisonhouse.com is used to obtain current warning data, which only goes back a few days. A more complete solution could use another source such as the NWS API Web Service. Much of the alert logic would need refactored to handle data from non-text sources, unless some sort of adapter can be created.

This archive data should be consistent with the timeline view, and provide additional details when hovering over the alert data on the map.

Keeping the AllisonHouse warnings around in some form should still be considered. Service reliability and delay must be taken into account.