Export ExtraInfo into ObXml

[gmella]

test could be done for the beginning of november for discussions with the Spica team

This should add key/value information in the ObXml file using the current asprox approach

[gmella]

First part done in aspro2. I will work on a2p2 side to walk in a simple manner to this new branch of data.

            <name>aNAME</name>
            <RA>1</RA>
            <DEC>2</DEC>
            <EQUINOX>2000.0</EQUINOX>
            <EXTRA_INFORMATIONS>
                <field xsi:type="a:StringValue" value="2" name="spicadb_id"/>
                <field xsi:type="a:StringValue" value="MOURARD" name="piname"/>
                <field xsi:type="a:StringValue" value="WP11" name="progname"/>

=>

SCTarget.EXTRA_INFORMATIONS.spicadb_id