Improve cmake find_package scanning for KDE/Qt

[phmccarty]

After extending the list of cmake module mappings recently (#628), find_package scanning has improved significantly.

The scanning can be further improved by scanning for COMPONENTS passed to find_package specifically for the Qt5 and KF5 packages. For those packages, each component indicates a module name, and that name is produced by appending the component name to the package name. For example, find_package(Qt5 ... COMPONENTS Core) should return the modules Qt5 and Qt5Core instead of just Qt5.

More extended examples can be found in this CMakeLists.txt; in particular, scanning these two commands:

find_package(Qt5 ${QT_MIN_VERSION} CONFIG REQUIRED COMPONENTS
    Core
    Concurrent
    DBus
    PrintSupport
    QuickWidgets
    Widgets
)

find_package(KF5 ${KF5_MIN_VERSION} REQUIRED
    CoreAddons
    Config
    I18n
    Declarative
    KIO
    Kirigami2
    Notifications
    Plasma
    Wayland
    WidgetsAddons
    WindowSystem
)

should produce these modules:

Qt5
Qt5Core
Qt5Concurrent
Qt5DBus
Qt5PrintSupport
Qt5QuickWidgets
Qt5Widgets
KF5
KF5CoreAddons
KF5Config
KF5I18n
KF5Declarative
KF5KIO
KF5Kirigami2
KF5Notifications
KF5Plasma
KF5Wayland
KF5WidgetsAddons
KF5WindowSystem