Move `declarativeimports/calendar` from plasma-framework to plasma-workspace

Summary

Files in plasma-framework/declarativeimports/calendar should be moved to plasma-worksapce, which is a prerequisite for adding the alternate calendar feature in Plasma.

Tasks

Choose a new import name for the calendar plugin

To keep compatible with old Plasma versions, the import name should be temporarily renamed until KF6 is released.

• Do you think org.kde.plasma.workspace.calendar is a good candidate?

Copy files

• Copy plasma-framework/declarativeimports/calendar to plasma-workspace/components (!1710 (merged))
• Rename org.kde.plasma.calendar to org.kde.plasma.workspace.calendar in the calendar plugin
• Replace org.kde.plasma.calendar with the new name in all files in Plasma

The usages of `org.kde.plasma.calendar` are listed in the table (2022-5-8).

Location	Related MRs
plasma-mobile/daykountdown/src/contents/ui/EventsCalendarPage.qml	https://invent.kde.org/plasma-mobile/daykountdown/-/merge_requests/2
plasma-mobile/daykountdown/src/contents/ui/SettingsPage.qml	https://invent.kde.org/plasma-mobile/daykountdown/-/merge_requests/2
plasma/kdeplasma-addons/applets/binary-clock/package/contents/ui/main.qml	kdeplasma-addons!149 (merged)
plasma/kdeplasma-addons/applets/fuzzy-clock/package/contents/ui/main.qml	kdeplasma-addons!149 (merged)
plasma/plasma-sdk/themeexplorer/package/contents/ui/delegates/analog_meter.qml	plasma-sdk!34 (merged)
plasma/plasma-sdk/themeexplorer/package/contents/ui/delegates/clock.qml	plasma-sdk!34 (merged)
plasma/plasma-workspace/applets/analog-clock/contents/ui/analogclock.qml	!1711 (merged)
plasma/plasma-workspace/applets/calendar/package/contents/ui/main.qml	!1711 (merged)
plasma/plasma-workspace/applets/digital-clock/package/contents/config/config.qml	!1711 (merged)
plasma/plasma-workspace/applets/digital-clock/package/contents/ui/CalendarView.qml	!1711 (merged)
plasma/plasma-workspace/applets/digital-clock/package/contents/ui/MonthMenu.qml	!1711 (merged)
plasma/plasma-workspace/applets/digital-clock/package/contents/ui/configAppearance.qml	!1711 (merged)
plasma/plasma-workspace/applets/digital-clock/package/contents/ui/configCalendar.qml	!1711 (merged)
plasma/plasma-workspace/applets/digital-clock/package/contents/ui/main.qml	!1711 (merged)

Test/Fix

Some features in the calendar plugin may not work as expected after finishing the steps above, so tests are needed. Auto test is better.

Click to expand

• plasma-mobile/daykountdown
• kdeplasma-addons/applets/binary-clock
• kdeplasma-addons/applets/fuzzy-clock
• plasma-sdk/themeexplorer
• plasma-workspace/applets/analog-clock
• plasma-workspace/applets/calendar
• plasma-workspace/applets/digital-clock