Add endpoint to get all skills

[MaartenS11]

New skills endpoint is at /skills this will return all skills present in the database.

Closes #218.

New feature checklist:

• I've added tests for the new feature (100% coverage)
• I've updated the osoc.yaml file

[codecov]

Codecov Report

Merging #232 (4f59f3e) into development (0c27fcb) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@                Coverage Diff                @@
##             development     #232      +/-   ##
=================================================
+ Coverage          95.47%   95.50%   +0.03%     
- Complexity           224      225       +1     
=================================================
  Files                 44       44              
  Lines                574      579       +5     
  Branches              42       42              
=================================================
+ Hits                 548      553       +5     
  Misses                16       16              
  Partials              10       10              

Flag	Coverage Δ
all_tests	95.50% <100.00%> (+0.03%)	⬆️

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Impacted Files	Coverage Δ
...e/osoc/team1/backend/controllers/BaseController.kt	100.00% <100.00%> (ø)
...am1/backend/controllers/CommunicationController.kt	100.00% <100.00%> (ø)
...tlin/be/osoc/team1/backend/services/BaseService.kt	100.00% <100.00%> (ø)
...soc/team1/backend/services/CommunicationService.kt	100.00% <100.00%> (ø)

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[Nyxes5]

Could you add a service test pls?

Done