Feature/drag and drop edges

[janniclas]

This pull request contains the functionality to drag and drop edges from existing components to reconnect them to another component.
Also multiple bug fixes and stability improvements of the graph module have been implemented

closes: #108 and #85

[codecov-io]

Codecov Report

Merging #115 into develop will decrease coverage by 0.17%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           develop    #115      +/-   ##
==========================================
- Coverage     4.52%   4.34%   -0.18%     
==========================================
  Files           12      12              
  Lines          221     230       +9     
  Branches        17      16       -1     
==========================================
  Hits            10      10              
- Misses         211     220       +9

Impacted Files	Coverage Δ
app/controllers/ApiRouter.scala	0% <0%> (ø)	⬆️
app/controllers/InstanceRegistryController.scala	0% <0%> (ø)	⬆️

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[johannesduesing]

As requested i did a functional test on this code, which already worked pretty well when i tested it with a rather big setup on the deployment server on Thursday. This time i used a smaller setup with 2 APIs and one WebApp.
It's working fine for me, re-assigning, coloring and hiding components and edges is working as expected. The only issue i can see is that you are currently able to re-assign a component to the same instance that it is already using, which is actually triggering a re-assignment call to the registry. I would expect to either hide the currently used dependency or just give the user a message that re-assignment is not needed because the desired dependency is already established.
Since i remember talking with @janniclas about this i'm not sure if that's intended behaviour for this PR, so i will still approve it in the current state.