correct mimetype location to follow the shared mime info specification

[Jan200101]

according to the shared-mime-info specification it should be installed into the packages folder:

Each application that wishes to contribute to the MIME database will install a single XML file, named after the application, into one of the three /packages/ directories (depending on where the user requested the application be installed). After installing, uninstalling or modifying this file, the application MUST run the update-mime-database command, which is provided by the freedesktop.org shared database[SharedMIME].

Unified system | Shared MIME-info Database

I saw that this change was made for FreeBSD but they seem to support the shared mime database

[LIJI32]

It's probably wise to uninstall the copy outside of packages/ that might have been there from a previous installation in the install target, otherwise you'd have two competing definitions.

[Jan200101]

I'm not so sure...
the codepath is only accessed when DESTDIR is set which I don't think a regular user would do, only system packages appear to be impacted by this changes