Merging type definitions with rpm-rs

[madonuko]

The current state of rpmspec-rs is "good enough" as in it can be used in production to read preambles. With that in mind, we probably might want to start merging code between rpmspec-rs and rpm-rs.

Personally I think it makes more sense for rpmspec-rs to use the types defined in rpm-rs as obviously they have a larger userbase and less cargo dependencies. In that case, the following entries need to be merged:

• %changelog
  • ChangelogEntry (requires parsing implementation, current one is broken and unused)
  • Timestamp
• %files
  • FileEntry
  • FileOptions
  • FileVerifyFlags
  • FileMode
  • PackageFileEntry
• Package
• Nevra
• Evr
• Scriptlet
• Dependency
  • DependencyFlags

[dralley]

The File* APIs probably need some adjustment, since as it stands they are barely usable IMO. But hooking it up to specfile parsing is probably a great way to sort out the issues and figure out what needs to be done about them.