Fix prompt coloring on Windows

MSP-11669

Set output stream for RbReadline (rl_outstream) to the
Rex::Ui::Text::Output::Stdio, which will use translate the ANSI color
escapes to set_color calls in Windows.
Error messages for the python meterpreter
Remove file exists check from stdapi_fs_delete_file
Land #4329, zeroSteiner's error messages for python meterpreter
Land #4337 - Fix prompt coloring on Windows