Since rclone version 1.61.0 the tree command uses ANSI color sequences in output by
default, but this lead to issues in Windows terminals that were not handling these (#6668).
This commit ensures the tree command uses the terminal package for output. It relies on
go-colorable to properly handle ANSI color sequences: If stdout is connected to a terminal
the escape sequences are decoded and the text are written with color formatting using
Windows Console API. If stdout is not connected to a terminal, e.g. redirected to file,
the escape sequences are stripped off. The tree command has its own method for writing
directly to a file, specified with flag --output, and then the output is not passed
through the terminal package and must therefore be written without ansi codes.
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