tool_doswin: Restore original console settings on CTRL signal

tool_doswin: Restore original console settings on CTRL signal

- Move Windows terminal init code from tool_main to tool_doswin.

- Restore the original console settings on CTRL+C and CTRL+BREAK.

Background: On Windows the curl tool changes the console settings to
enable virtual terminal processing (eg color output) if supported
(ie Win 10). The original settings are restored on exit but prior to
this change were not restored in the case of the CTRL signals.

Windows VT behavior varies depending on console/powershell/terminal;
refer to the discussion in #6226.

Assisted-by: Rich Turner
Closes https://github.com/curl/curl/pull/6226