feat(weekView): Allow drag outside calendar view

[ElieSauveterre]

External events can be drag'n'drop from the calendar view to a drop zone

[mattlewis92]

Thanks for this! Rather than removing the old functionality can we retain the existing behaviour and have this opt in via an option like [allowDragOutside]="true".

[ElieSauveterre]

@mattlewis92 It's done. What do you think ?

[codecov-io]

Codecov Report

Merging #214 into master will increase coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #214      +/-   ##
==========================================
+ Coverage   96.99%   97.04%   +0.05%     
==========================================
  Files          30       30              
  Lines         565      576      +11     
  Branches       45       49       +4     
==========================================
+ Hits          548      559      +11     
  Partials       17       17

Impacted Files	Coverage Δ
src/components/week/calendarWeekView.component.ts	94.73% <100%> (+0.68%)	⬆️

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[mattlewis92]

@ElieSauveterre I've tweaked the logic so that if a user drags the event outside of the calendar view the event start and end dates are always changed by a fixed number of days rather than using the start and end of the week - what do you think?

[ElieSauveterre]

@mattlewis92 That's better. Thanks.

[mattlewis92]

Released as 0.16.0, thanks for the contribution! 👍