Remove python-rclone dependency

[MitchellThompkins]

PR Message

Title: Refactor: Remove python-rclone dependency and update to v0.1.7

Description:
This PR removes the dependency on the python-rclone library and refactors the decryption logic to use Python's subprocess module to call rclone directly. This change reduces external dependencies and improves long-term maintainability.

Key Changes:

• Removed python-rclone Dependency: Cleaned up pyproject.toml and requirements.txt.
• Refactored decrypt.py:
  • Replaced rclone library usage with direct subprocess calls.
  • Updated get_rclone_config_path to return the path to a temporary config file instead of an rclone instance.
  • Updated rclone_copy to use the rclone CLI for listing remotes and copying files.
• Dynamic Config Detection: Implemented dynamic detection of the default rclone configuration file path using rclone config file, which improves cross-platform reliability and removes hardcoded path assumptions.
• Version Bump: Updated project version from 0.1.6 to 0.1.7.
• GUI Support: Removing tk GUI support for now.

Testing:

• Verified all 9 tests in tests/test_rclone_decrypt.py pass.
• Confirmed that file decryption remains fully functional across various encryption scenarios.