[Libosinfo] Volume-size patch series

[Zeeshan Ali (Khattak)]

This series of patches,

1. Makes it possible to specify volume-size for ISO media entries.
2. Make use of volume-size for detection. This is actually the main point of all this effort. Many times the volume-id is the same for different medias of the same OS and hence volume-id makes it much easier to differetiate between those different medias.
3. Add volume-size info to fedora medias.
4. Add many missing Fedora testcases.