Log Message:
Update multimedia/assimp to version 5.2.3

Update multimedia/assimp to version 5.2.3.

The reason for updating is that this
version has changes, mOrthographicWith in
aiCamera, needed by some packages in wip
(qt6).

This update should be safe since only wip
packages depend on it.

pkgsrc changes:
patch-assimp.pc.in came from upstream and
is now removed.
contrib/irrXML does not exist anymore so
patch-contrib_irrXML_CMakeLists.txt has
been removed.

Changes in package:
To many to mention.