OpenXML Filter: XLSX: allow the extraction of the specified cells only

The idea is to limit the extraction from source to target columns that are only mentioned in the worksheet configurations. For instance:

A document: image

With the following configuration:

extractExcelSourceAndTargetColumnsJoined.b=true
worksheetConfigurations.0.namePattern=Sheet1
worksheetConfigurations.0.sourceColumns=A,C
worksheetConfigurations.0.targetColumns=B,D
worksheetConfigurations.number.i=1

Would be extracted as:

<group id="P76C545-sg1" resname="Sheet1">
<group id="P132303AB-sg1" resname="1">
<trans-unit id="P147242AB-tu1" resname="Sheet1!B1" xml:space="preserve">
<source xml:lang="en-US">source a</source>
<target xml:lang="fr-FR">target a</target>
</trans-unit>
<trans-unit id="P147242AB-tu2" resname="Sheet1!D1" xml:space="preserve">
<source xml:lang="en-US">source c</source>
<target xml:lang="fr-FR">target c</target>
</trans-unit>
</group>
</group>

Please note the absence of the "out-of-scope" value.

The example document - explicit-cells.xlsx