Merge branch 'feature/562-SET-signature-check' of https://git.fitko.de/fit-connect/sdk-dotnet into feature/562-SET-signature-check

# Conflicts:
#	BasicUnitTest/SecurityEventTokenTests.cs
#	BasicUnitTest/SenderTests.cs
#	E2ETest/RejectSubmissionTest.cs
#	FitConnect/Client.cs
#	FitConnect/Encryption/FitEncryption.cs
#	FitConnect/FitConnectClient.cs
#	FitConnect/Interfaces/IFitConnectClient.cs
#	FitConnect/Interfaces/Sender/ISenderWithService.cs
#	FitConnect/Models/Callback.cs
#	FitConnect/Models/FitConnectEnvironment.cs
#	FitConnect/Models/SecurityEventToken.cs
#	FitConnect/Router.cs
#	FitConnect/Sender.cs
#	FitConnect/Services/Interfaces/ISelfServicePortalService.cs
#	FitConnect/Services/Models/v1/Routes/Routes.cs
#	FitConnect/Services/SelfServicePortalService.cs
#	FitConnect/Services/SubmissionService.cs
#	FitConnect/Subscriber.cs
#	IntegrationTests/JwtTokenValidation.cs