Fix missing `TEMP` and `TMP` environment variables

- All windows templates: Added `TEMP` and `TMP` variables as Cygwin doesn't pass them to `cmd`
- All windows scripts: Changed `%LOCAL_TEMP%` to `%TEMP%` now that it's properly initialized
- All windows templates: Fixed `USERNAME` variable as Cygwin sets this to `cyg_server`
- All windows templates: Changed `C:/cygwin/tmp/script.bat` to `$(/bin/cygpath -m '{{.Path}}')`
- All `vagrant.bat`s: Use `%USERPROFILE%` as it's always available
- All `vmtools.bat`s: Standardized (use `if exist "%SystemDrive%\Program Files (x86)"` throughout)
- All `vmtools.bat`s: Delete all downloads after use
- All `vmtools.bat`s: Quoted paths, as appropriate
- All `.bat` files: Removed `endlocal`s, as it's implied (see `SETLOCAL /?`)