Endpoints for /search, /retrieve and /features do not work on windows machines

[johannesduesing]

Describe the bug
When running the WebApi on Windows 10, any call to /search, /retrieve or /features will yield a 500 Internal Server Error. The Log shows:

java.nio.charset.UnmappableCharacterException: Input length = 1

To Reproduce
Steps to reproduce the behavior:

1. Clone the repository on Windows 10
2. Set a valid elasticsearch host in the Configuration
3. Execute sbt run
4. Any call to the endpoints mentioned above will results in an Internal Server Error

Expected behavior
I would expect the endpoints to behave normally and return results

Screenshots
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Affected components (if known)
webapi

Desktop (please complete the following information, if relevant):

• OS: Windows 10

Additional context
All listed endpoints read the "features.json" file from the application's resources. That file is UTF-8 encoded, and i suspect that the webapi is trying to access it with a platform-dependent encoding, which on linux works, but on windows does not.

[johannesduesing]

Closed with #58