Support for flashing without mbedls

## Flashing a single device

```
>>> flasher.flash(build="C:\\path_to_file\\myfile.bin", target_id="0240000028884e450019700f6bf0000f8021000097969900", platform_name="K64F")
```

**optional**
- platform_name
- mount_point
- serial_port

If all required fields are available do not call mbedls at all (possible to use without mbedls)

Start at the flasher.flash entry point shown in the issue and trace where mbedls is called. Verify the supplied build, target_id, platform_name, mount_point, and serial_port are sufficient to flash one device without invoking mbedls, then confirm the documented single-device example works.

Written by the indexing model from the issue text.