Implemented prototype and proof-of-concept for time window pager.

The reporting dashboards now demonstrate new feature: quick search options and time window paging. For performing common quick searches it is now possible to choose the appropriate option from presented list and get results without choosing the time windows manually. Additionally the result page for this quick search option provides means for paging back and forward in time with appropriate time window. For example you may search for current month and then use the time window paging to get results for previous month. (Redmine issue: #4321)