Refactor downloader and file manager for improved rclone integration and add healthcheck and smoke test options

- Renamed download flags in ContentDownloader for clarity.
- Enhanced FileManager with methods to build upload paths and verify existing files for rclone uploads.
- Updated StreamProcessor to return success status for stream processing.
- Added rclone smoke test and healthcheck functions to validate configuration and tool availability.
- Improved environment variable handling with a utility function.
- Updated TwitchArchive to incorporate new rclone verification and processing logic.
- Added unit tests for new functionality and refactored existing tests for clarity and coverage.

Co-authored-by: Copilot <copilot@github.com>

dockerstart.bat

@@ -0,0 +1,20 @@
+@echo off
+setlocal
+
+if "%~1"=="" (
+    echo Usage: .\dockerstart.bat streamer [additional args]
+    exit /b 1
+)
+
+set STREAMER=%~1
+shift
+
+set EXTRA_ARGS=
+:collect_args
+if "%~1"=="" goto run_compose
+set EXTRA_ARGS=%EXTRA_ARGS% %~1
+shift
+goto collect_args
+
+:run_compose
+docker compose --env-file .env.development -f docker-compose.yml -f docker-compose.override.yml run --rm twitch-archive python twitch-archive.py -u %STREAMER%%EXTRA_ARGS%