chore: extract reusable QML components to logos-qml-components repo

[jimmy-claw]

As Scala, Lope, and other Logos Core apps grow, shared QML components will be needed by all of them.

Proposed: jimmy-claw/logos-qml-components

Initial components:

• DateTimePicker.qml (feat: date/time picker for event modal #28)
• Any other reusable pickers/dialogs as they emerge

Usage

# In consuming apps
FetchContent_Declare(logos-qml-components
    GIT_REPOSITORY https://github.com/jimmy-claw/logos-qml-components
    GIT_TAG main
)

Consistent UX across the entire Logos app ecosystem.