Improve Error Reporting for Executed Commands

[fabquenneville]

Description:
Currently, when a command fails during execution, the error message is printed in a Python list format, making it less readable. For example, the output looks like this:

Conversion failed Command '['ffmpeg', '-i', 'input.mkv', ...] returned non-zero exit status 1.

This format can be confusing for users who may not be familiar with Python lists. To enhance clarity and usability, I propose that the executed command be printed as a bash command instead.

Proposed Format:
The error message should be reformatted to provide clearer information about the failure. The output should look like this:

Conversion failed
Command: ffmpeg -i input.mkv ...
Error: returned non-zero exit status 1.

Benefits:

• Improved readability of error messages.
• Easier for users to quickly identify the command that failed.
• More intuitive for those familiar with bash commands rather than Python syntax.

Steps to Reproduce:

1. Execute a command using mediacurator that is expected to fail.
2. Observe the current error message format.

Expected Outcome:
The error message should follow the proposed format, providing better context and clarity for troubleshooting.

Actual Outcome:
The error message is currently output as a Python list, which is less readable.