Fix force insert

[regisoc]

This PR adds a new required tag in xml file called VR that is required when using forceInsert tag.
Each fields that is not present needs a type setting which needs to be added manually.
The complete list is here: https://pydicom.github.io/pydicom/stable/guides/element_value_types.html

A forceInsert tag should also include a VR tag such as

<item>
      <name>0008,0022</name>
      <description>AcquisitionDate</description>
      <editable>no</editable>
      <forceInsert>yes</forceInsert>
      <VR>DA</VR> 
</item>