OpenXML Filter: XLSX: allow the exposition of maxwidth and size-unit properties per target column

Translation units can be accompanied by max-width and size-unit properties, which can be specified per worksheet and target column.

This can be achieved by adding a specific worksheet configuration option, e.g. targetColumnsMaxCharacters.

E.g.: for the picture below:

The extraction to XLIFF may look like:

<group id="P76C545-sg1" resname="Sheet1">
<group id="P132303AB-sg1" resname="1">
<trans-unit id="P147242AB-tu1" resname="Sheet1!A1" xml:space="preserve">
<source xml:lang="en">Text 1</source>
<target xml:lang="fr"></target>
</trans-unit>
<trans-unit id="P147242AB-tu2" resname="Sheet1!B1" maxwidth="5" size-unit="char" xml:space="preserve">
<source xml:lang="en">B1</source>
<target xml:lang="fr"></target>
</trans-unit>
</group>
<group id="P132303AB-sg2" resname="2">
<trans-unit id="P147242AB-tu3" resname="Sheet1!A2" xml:space="preserve">
<source xml:lang="en">Text 2</source>
<target xml:lang="fr"></target>
</trans-unit>
<trans-unit id="P147242AB-tu4" resname="Sheet1!C2" maxwidth="2" size-unit="char" xml:space="preserve">
<source xml:lang="en">C2</source>
<target xml:lang="fr"></target>
</trans-unit>
</group>
<group id="P132303AB-sg3" resname="3">
<trans-unit id="P147242AB-tu5" resname="Sheet1!B3" maxwidth="5" size-unit="char" xml:space="preserve">
<source xml:lang="en">B3</source>
<target xml:lang="fr"></target>
</trans-unit>
</group>
</group>

A sample styled-and-plain-strings.xlsx document is attached for observations.