Presentation.xml: Building different variants of identifiers

[manuelfuenmayor]

In relation to #1250

Description of the issue

Original version of iso-8601-2-amd1 document uses two identifier variants:

In presentation.xml we are given 4 docidentifier tags:

<docidentifier type="ISO" primary="true">ISO 8601-2:2019/PRF Amd 1:2024</docidentifier>
<docidentifier type="iso-reference">ISO 8601-2:2019/PRF Amd 1:2024(E)</docidentifier>
<docidentifier type="URN">urn:iso:std:iso:8601:-2:ed-1:stage-draft:amd:2024:v1</docidentifier>
<docidentifier type="iso-tc">ISO/TC 154 N 1535</docidentifier>

However, these are pre-built identifiers. They don't give too many options to match with original format.
In PDF, @Intelligent2013 used <docidentifier type="ISO" primary="true"> to get the identifier.
Therefore, the output looks like this:

I think presentation.xml should provide more options to build more than one variant of identifier.

To reproduce

Go to iso-8601-2-amd1 and execute:

$ bundle exec metanorma -x pdf sources/iso-8601-2-amd-1.adoc