Added Stats chart for org template usage

The "No. plans by template" statistics and visualisation changes: ...

(1) The headers for the CSV for the Number of Plans by Template
             - the date column have dates in the format  'Jan 2018'
             - the template headers now display the Title of the templates
             - the Date and Count headers are capitalized.

        (2) The chart has been re-styled.
            The aspect ratio (width/height) of image is now dynamically
            set according to the selection of the month range.

        (3) Fixed broken rspec tests and rubocop errors/warnings.

        Fix for #1679.

1. stat_created_plan.to_csv with option for details by template. ...

2. details attribute for stats table #1679
3. create_created_plan_service extended with details by template
4. create_last_month_created_plan_service extended with details by
template.
5. create_or_update strategy for generating stats
6. StatCreatedPlanByTemplateController#index for graphs usage
7. month_start_date and month_end_date for OrgDateRangeable class

[RD-1679] Usage view including date input for plans by template

[#1679] monthly_range query updated

[#1679] client-side chart for plans by template

[#1679] Time picker for plans by template chart

[#1679] Download plans by template action.

deleted spec

merge conflicts fixed

[#1679] Removed JS linter warnings

[#1679] Rubocop conforming code. Drying out stat services

Merge pull request #1989 from DMPRoadmap/issue-1161 ...

Issue #1161 - Display tooltip below form fields on Create plan page.