Libreoffice deps update.

[arrowd]

Summary

textproc/libixion: Add the new port.

Ixion is a general purpose formula parser, interpreter, formula cell dependency
tracker and spreadsheet document model backend all in one package.

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devel/mdds: Update to 2.0.0

While there, switch the distfile to .xz

Test Plan

poudriere testport passes for both ports on 14-CURRENT

[fluffy]

I suggest to add PLIST_SUB= VERSION=${PORTVERSION:R} to Makefile for libixion and relpace all "0.17" with %%VERSION%% macro in plist for easy future updates

[arrowd]

Add VERSION plist substitution.

[arrowd]

Landed somewhen else.