Add xx-messenger example

...xcassets/AppIcon.appiconset/iPad Notification 20pt 1x.png

...xcassets/AppIcon.appiconset/iPad Notification 20pt 2x.png

...AppIcon.appiconset/iPad Pro (12.9-inch) App 83.5pt 2x.png

...ets.xcassets/AppIcon.appiconset/iPad Settings 29pt 1x.png

...ets.xcassets/AppIcon.appiconset/iPad Settings 29pt 2x.png

...ts.xcassets/AppIcon.appiconset/iPad Spotlight 40pt 1x.png

...ts.xcassets/AppIcon.appiconset/iPad Spotlight 40pt 2x.png

...Assets.xcassets/AppIcon.appiconset/iPhone App 60pt 2x.png

...Assets.xcassets/AppIcon.appiconset/iPhone App 60pt 3x.png

...assets/AppIcon.appiconset/iPhone Notification 20pt 2x.png

...assets/AppIcon.appiconset/iPhone Notification 20pt 3x.png

...s.xcassets/AppIcon.appiconset/iPhone Settings 29pt 2x.png

...s.xcassets/AppIcon.appiconset/iPhone Settings 29pt 3x.png

....xcassets/AppIcon.appiconset/iPhone Spotlight 40pt 2x.png

....xcassets/AppIcon.appiconset/iPhone Spotlight 40pt 3x.png

...ssenger/Project/XXMessenger/Assets.xcassets/Contents.json

Examples/xx-messenger/README.md

...es/xx-messenger/Sources/AppCore/DBManager/DBManager.swift

...-messenger/Sources/AppCore/DBManager/DBManagerGetDB.swift

...-messenger/Sources/AppCore/DBManager/DBManagerHasDB.swift