Add timeline helper classes

#refs 4190
Add timeline controller

refs #4190
Fix type specification in DowntimestarthistoryQuery

refs #4190
Make TimeEntry creation more flexible

TimeEntry objects are now created with the fromArray
constructor instead of the default one.

refs #4190
Add interval selectbox and group legend

refs #4190
Fix license header

refs #4190
Return timeframes when iterating over TimeRange objects

refs #4190
Implicitly add an TimeEntry's weight when calling getValue()

refs #4190
Fix some bugs in the TimelineController

refs #4190
Implement timeline rendering

refs #4190
Improve timeline layout

refs #4190
Fix event interpolation

refs #4190
Clientside scrolling implementation [WIP]

refs #4190
Move timeline classes into the monitoring module

refs #4190
Make interval selection being a widget

refs #4190
The timeline object is NOT a form

refs #4190
Fix that the queryfilter parser cannot handle integer values
Fix that the TimeRange cannot handle events occured at full hours

refs #4190
Refactor timeline components

refs #4190
Make GET param of interval selection widget more generic