These provides are specifically for packages providing
AppStream files, which are either going to be *.appdata.xml
or *.metainfo.xml files in /usr/share/appdata or /usr/share/metainfo.
The upstream AppStream specification mandates *.metainfo.xml files
installed into /usr/share/metainfo, but there's still a large body
of legacy AppStream files installed in the legacy location.
For now, let's support both under the new metainfo() Provides.