Introduces a new fmt based logging system to replace the previous
Qt-based logging mechanism.
Key features:
- Logging macros (LogD, LogI, LogW, LogE, LogF) for different levels.
- Configurable log levels and backends (Console, Journal).
- Configuration via environment variables (LINYAPS_LOG_LEVEL,
LINYAPS_LOG_BACKEND) for flexible control.
- Integration with systemd-journal for structured logging, including
code location (file, line, function).
- Custom `fmt` formatters for `QString`, `QStringList`, and
`linglong::utils::error::Error`.
- New string utility functions (`stringEqual`, `splitString`) are added.
The `qdebug_helper.h` is removed as part of this transition.
Signed-off-by: reddevillg <reddevillg@gmail.com>
ccdc5dd9df