refactor routine to habit;
use HabitStatus instead of HistoricalStatus and PlanningStatus;
add additional statuses for clarity;
rewrite logic of habit status computation so that both: historical and future statuses can be computed on the go instead of being cashed in the database, the only data that needs to be stored is number of times completed;

Add the corresponding fakes and refactor some existing data sources

Refactor Routine to Habit

Refactor Routine to Habit along the way.

The app currently works well, but the habit streak functionality is not working. It always displays zeros in the current/latest streak cards. Streak functionality is also required to determine the color of an ambiguous date in RoutineCalendar, such as one that is associated with NotDue or Skipped habit status. So these days are displayed with the green (completed) color at the moment.

The is also a lot of minor improvements and fixes to be done including refactoring Routine to Habit in the scope of the whole project

The detailed list of changes will be written upon the MVP release along with documenting the project, providing it's description in README.md, etc.

Increase the speed of habit statuses computation on RoutineCalendarScreen by computing each date in a separate coroutine
Introduce pagination for RoutineCalendarScreen so that the status computation process is not visible to the user

Improve RoutineCalendarViewModel's code
Configure pagination for RoutineCalendar
Move habit status computation off the main thread but only in RoutineCalendarViewModel (bad practice, should be fixed soon)

Keep Routine in all places where it represents an abstract term and may imply a simple task, for example.

To document the changes in the #6 PR

- Don't fetch data from repository in for loops in HabitComputeStatusUseCase. Instead, get lists of data only once and then operate on them.
- Add new functionality to vacation data sources.
- Optimize coroutines in RoutineCalendarViewModel.
 They now get cancelled when the data gets outdated. This way, we don't waste resources because the same month's data is not loaded simultaneously.

Calendar dates have been loading rather slowly after a completion, especially when multiple dates were clicked at the same time. To sort out this issue, I changed the code to reload only the current month and delete all the others. Although with this approach, a visible delay in data load gets appeared upon scroll to another month, this issue is minuscule compared to the previous ones.

- Switch to Dispatchers.Default in HabitComputeStatusUseCase instead of doing that in RoutineCalendarViewModel
- Minor fix - classify already completed status to two status for future and past dates. That's necessary because the RoutineCalendar will display wrong colors for future dates otherwise
- Don't provide Dispatchers.IO with Koin because it provides this dispatcher for all coroutine contexts, which is an undesired behaviour. Make it a default value for all existing local data sources instead.

to show routines only when they are loaded