Reporting: display alert report (col sizing, filtering, etc)

[dasgarner]

Various improvements to the display alert report:

• Range filtering once Range filters should be improved to work mostly client side #2732 is completed.
• Column sizing
• Duration column (blank if a single point in time)
• Event Type filtering (+ any other appropriate filters)

It would also be nice to consider a visualisation of some sort; please have a think about what might be appropriate (something like a Gantt chart perhaps?)