#1371 More specific selector for usage statistics export button

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

Update asset structure with webpacker gem