68280686 Task deadlines implementation

- setup bootstrap-datepicker-rails
- added deadline field
- added displaying of deadline via tooltip
- added red color indication on overdue tasks
67642438 Content records order and filters

- set order fot content records as ref_no asc
- added ajax search filters for title, platfrom and status with pagination
- setup javascript testing via poltergeist
- covered ajax filtering of content records with Rspec tests
Merge pull request #56 from bitzesty/68280686-tasks-implemented-deadlines

68280686 Task deadlines implementation
Merge pull request #57 from bitzesty/67642438-content-records-filters

67642438 Content records order and filters