[4.1 only] feat(compiler): support ICU messages in XLIFF

[marclaval]

Fixes #12636

After discussion, we decided to implement the solution 4 from the research document: https://docs.google.com/document/d/1FS02wIBSEbysCoxEqbEmJg3_LyfJ566DZLhhbOUheoA/edit?usp=sharing

[vicb]

any reason to modify this ?

Is this only to reflect changes in he xmb ?

[marclaval]

Same story as for the XTB loader: translations are first retrieved as string so that ICU messages can be parsed before xml nodes.

[vicb]

LGTM with one question

[ocombe]

Missing type on c

Changes done

[rodush]

I hope it also fixes the issue of 2.4.8 - when a bit more complex than just basic "select" statement is not extracted into XLIFF file at all...
Example of text:

<ng-container i18n="main-nav.opening-hours|Texts representing opening hours">
    {
        statusText.label, select,
            opening-hours.opened {Nu open (tot {{ statusText.time }})}
            opening-hours.open-tomorrow {Morgen om {{ statusText.time }} zijn we weer open}
            opening-hours.closed {Nu gesloten (we gaan open om {{ statusText.time }})}
            opening-hours.closed-till {Nu gesloten (we gaan maandag open om {{ statusText.time }})}
    }
</ng-container>

where statusText is an object assigned in component, has view e.g.: let statusText = {label: 'opening-hours.opened', time: '18:00'}
Could you guys make sure in your tests that this is extracted properly and translatable.
Thanks!

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