Fixed some DTOs

.docs/.openapi/api-data.yaml

.docs/.openapi/api-metadata.yaml

.docs/.openapi/api.base.yaml

.docs/.openapi/swagger-ui.html

...e/api/src/main/java/at/tuwien/api/auth/CreateUserDto.java

...pi/src/main/java/at/tuwien/api/auth/SignupRequestDto.java

...c/main/java/at/tuwien/api/database/CreateDatabaseDto.java

...i/src/main/java/at/tuwien/api/database/CreateViewDto.java

...ain/java/at/tuwien/api/database/table/CreateTableDto.java

...wien/api/database/table/columns/CreateTableColumnDto.java

...database/table/constraints/CreateTableConstraintsDto.java

...tabase/table/constraints/foreign/CreateForeignKeyDto.java

...at/tuwien/api/database/table/internal/TableCreateDto.java

...in/java/at/tuwien/api/identifier/CreateIdentifierDto.java

...main/java/at/tuwien/api/identifier/IdentifierSaveDto.java

...va/at/tuwien/api/identifier/SaveIdentifierCreatorDto.java

...t/tuwien/api/identifier/SaveIdentifierDescriptionDto.java

...ava/at/tuwien/api/identifier/SaveIdentifierFunderDto.java

...java/at/tuwien/api/identifier/SaveIdentifierTitleDto.java

...va/at/tuwien/api/identifier/SaveRelatedIdentifierDto.java