Refactor platform plugin code

[plfiorini]

• [x] Put all platform support code ander the Aurora::PlatformSupport namespace
• [x] Rename AuroraXkbcommon classes to fit our naming convention
• [x] Merge AuroraXkbcommon and eglfsxkb code
• [x] Integrate AuroraUdev code with AuroraLogind instead of duplicating the logind code
• [x] Rename edid classes to fit our naming convention
• [x] Rename kmsconvenience classes to fit our naming convention