chore: remove static field initializers from enums, simplify fromValue loop

...ava/de/fitko/fitconnect/api/domain/model/jwk/AlgEnum.java

.../java/de/fitko/fitconnect/api/domain/model/jwk/EEnum.java

.../de/fitko/fitconnect/api/domain/model/jwk/KeyOpsEnum.java

...ava/de/fitko/fitconnect/api/domain/model/jwk/KtyEnum.java

...itconnect/api/domain/model/metadata/EidasAdesProfile.java

...fitconnect/api/domain/model/metadata/SignatureFormat.java

...connect/api/domain/model/metadata/attachment/Purpose.java

...etadata/attachment/signature/AttachmentSignatureType.java

...ect/api/domain/model/metadata/data/DataSignatureType.java

...o/fitconnect/api/domain/model/metadata/data/MimeType.java