feat(webview): add a log view to simplify log access and support

[JakobLichterfeld]

As a user, accessing TeslaMate logs can be difficult. Providing simple access to logs from Webview could improve self-support.

As a maintainer, it is time-consuming when users do not provide logs when reporting issues. If access to logs were easier, this would reduce the number of back-and-forth exchanges.

[JakobLichterfeld]

Points to consider:

• Webview log access to complete log.
  • Don't load entire large files. Read only necessary parts (e.g., last N lines, paginated) -> Implement a "tail" or pagination in LiveView.
• Restrict access to authenticated UI
• Prevent really big log files (Rotate logs to prevent unbounded growth)
• pure elixir solution
• UI to enable/disable file logging and environment variable control. (TESLAMATE_FILE_LOGGING_ENABLED)
  • Log File Location (Persistence & Permissions):
    • User-configurable TESLAMATE_FILE_LOGGING_PATH or a persistent subdirectory within the application's working directory (e.g., data/logs/teslamate.log).
• Minimize write cycles (for Raspberry Pis with SD cards as disks for example)
• Logs persistent across reboots

[JakobLichterfeld]

First playground: #4898