Various improvements and some fixes

- Various adaptations for Debian 12 (Bookworm)

- showcase: Move all demo-related parts to a new subproject 'showcase'

- resources: Extend API, make state attribute methods like 'isBusy()' available in 'CResource'
- resources: Add new type 'rcPower'; add 'CRcValueState::ToHuman()'
- resources: Add support for info/warning messages by script drivers; Fix driving for keep-running drivers; Add capturing of stderr

- brownies: Add retry loop to 'IfElvI2cInit()', closes Github pull request #4 ("Retry code for failing ELV-USB-I2C device")
- brownies: Fix permanent 'rcsBusy' state of shades on startup

- mqtt: Correction of mqttWillPayload length (#6)
- mqtt: Add support for JSON payloads

- drivers: Add fingerprint driver (R503) and support tool
- drivers: Add 'fronius' driver

- wallclock: Add energy meter; some cleanup
- wallclock: Upgrade to SDL 2.28.5 and SDL_ttf 2.20.2

- wallclock/floorplan: Improve floorplan and add support for custom icons
- wallclock/floorplan: add tool 'home2l-icon' to prepare custom icons
- wallclock/floorplan: add icons "fingerprint", "security" and "pool"
- wallclock/floorplan: add option "attention" to customize the use state from which attention is drawn
- wallclock/floorplan: improve visibility of busy resources
- wallclock/floorplan, enocean: Make window handles writeable and allow to dismiss attention via UI

- wallclock/music: Add option to update the database on the MPD server.
- wallclock/music: Fix unsorted playlist listing
- wallclock/music: Fix streamer issues and improve error handling

- wallclock/calendar: Improve error handling and fix overflow on remind parsing
- wallclock/calendar: Add time-out for reloading calendars
- wallclock/calendar: Integrate 'patch' into Android app to fix calendar edit failures
- wallclock/calendar: Integrate remind to make calendar run on Android without Linux host

- wallclock/android: Rearrange directory structure for contemporary Android building using Gradle (UNTESTED, no code changes)
- wallclock/android: Make APK building independent from environment settings (ANDROID_...)
- wallclock/android: Cleanup APK code; drop sync2l interface; drop immersive mode
- wallclock/android: Adapt to build with SDK 34 and NDK r25, OpenJDK 17
- wallclock/android: New mechanism for /etc updates without requiring root on Android device
- wallclock/android + home2l-adb: Add resource to support ADB over TCP with remote enabling
- wallclock/android: Upgrade to Gstreamer 1.20.7

Various minor fixes and improvements; Ready for version 1.2

Add binary docs for v1.0

Update .gitattributes