Implement Due Dates dashboard

[julen]

When users are on any language-specific page (including language home page), they should see a prominent block (Dashboard), which is inserted between the top (dark gray) panel and navigation pane (light gray).


The section has the ": Things To Do Next" title and up to three items, in the order of importance. The dashboard always shows the same tasks for any page under a given language.

The "Show more" link is shown when there are more than 3 tasks with due dates registered. Clicking on it will add 5 more tasks to the bottom each time (until there are no more tasks).

Task importance

Most important tasks appear on top. Critically important ones are additionally displayed in red color throughout the UI.

A task is considered critical if either:

1. due date is within 3 business days, or
2. number of words divided by number of business days is more than a certain configurable threshold (set it to 2000 by default, which is a low average value for a full-time translator).

Sorting should happen like this: critical tasks go first; within critical tasks bucket and within non-critical tasks bucket sorting must be done by due date, ascending.

Task rendering

The actual rendering for these tasks will differ depending on the user permissions. If the user has submission rights, they will see:

1. "Fix Critical Errors" (all critical errors need to be fixed)
2. "Finish Translation" (all units need to be translated, including fuzzy units)

If the user has only suggestion rights, they will see only the following:

1. _"Finish Suggesting" (there should no longer be any untranslated units with no suggestions)

Reviewing all suggestions by a due date should not be considered a priority task by default.

When there are no tasks with due dates, we can show up to three default tasks in the order depicted below (fix errors, if any; finish translations, if any; review suggestions, if any):

If there are no tasks to display (everything is translated and there are no critical errors and no suggestions to review), a placeholder is shown:

Task completion

When a task is completed, it is removed (hidden) from the dashboard. Completion means that the number of incomplete units is zero for the "Finish translation" task and number of units with critical errors is zero for the "Fix Critical Errors" task.

If some new strings appear inside the given pootle path, the task will resurface in the dashboard. Managers need to explicitly delete obsolete tasks or change their date to some future one from the admin UI.

Prerequisites

• Admin widget in browsing pages (Add Due Dates widget in browsing pages #4801)
• Implement reusable components:
  • TranslationProgress
  • Count (pill)