Consider changing logging support to env_logger

[volks73]

The loggerv crate uses the ansi_term crate for colorized output, so enabling ANSI escape sequences on Windows 10 is still needed to prevent preventing ANSI escape characters in the log messages. The ansi_term and atty crates dependencies still exist.

I believe the same verbosity-based logging functionality can be achieved with the env_logger crate, which uses the termcolor crate for coloring and would also add setting the log level from an environment variable.

It should be noted that the clap crate also uses the ansi_term crate for coloring but it handles the enabling of ANSI escape sequences for Windows 10 internally. Another alternative would be to add this internal functionality to the loggerv crate.

[volks73]

It appears for clap v3, the project is moving away from ansi_term to termcolor as well.

[volks73]

I went ahead and did the conversion from loggerv to env_logger but was able to add a custom format that mimics the loggerv defaults and verbosity-based level selection. The requirements for enabling ANSI support on Windows 10 for the log messages has been removed.

Resolved as of ad4b008.