Fix: Allow code value greater than 16
This (partly) aligns the creation of dicom code values with the standard.
According to the reference:
The Long Code Value (0008,0119) or URN Code Value (0008,0120) is only used for codes that exceed the 16-character size limit of Code Value (0008,0100).
If the code value length exceeds 16, the Code Value (0008,0100) shall not be present. If the code value length is 16 characters or less,
the Code Value (0008,0100) shall contain the code and neither Long Code Value (0008,0119) nor URN Code Value (0008,0120) shall be present.
The URN Code Value (0008,0120) shall be used for codes that are represented using URN or URL notation.
The Long Code Value (0008,0119) shall be used for codes that are represented using other notations and that exceed 16 characters in length.
This merge request allows for codes of length > 16 to be made with type UC (selon innolitic).
This merge request does not implement the URN code type as I have no idea how I would do that.
This is necessary as some code standards like Snowmed CT has really long code values
Edited by Ronan Lefol