Add Origin property to the GiftCard

[Roshyo]

Also define this property automatically according to where it has been created.

Fix #166

[codecov]

Codecov Report

Merging #171 (67e44f7) into 0.12.x (bc85b3f) will increase coverage by 0.84%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             0.12.x     #171      +/-   ##
============================================
+ Coverage     37.72%   38.57%   +0.84%     
- Complexity      447      454       +7     
============================================
  Files            87       88       +1     
  Lines          1450     1470      +20     
============================================
+ Hits            547      567      +20     
  Misses          903      903              

Impacted Files	Coverage Δ
...tionExtension/GiftCardsByLoggedInUserExtension.php	100.00% <ø> (ø)
src/Api/DataPersister/GiftCardDataPersister.php	100.00% <100.00%> (ø)
src/Factory/GiftCardFactory.php	100.00% <100.00%> (ø)
src/Model/GiftCard.php	71.57% <100.00%> (+1.24%)	⬆️

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[loevgaard]

Veeery nice PR 🎉