Multiple device registration causes KID error

[rashedtalukder]

If the registration script is run for a second+ device after the first one, it results in a kid error due to the manifest handler only accepting 1 file in the output_files path. Solution is to 1/ reuse signer cert if it exists 2/ generate unique cert names using the serial number and match against manifest name.

Traceback (most recent call last):
  File "/Core2-for-AWS-IoT-EduKit/Blinky-Hello-World/utilities/AWS_IoT_registration_helper/registration_helper.py", line 215, in <module>
    main() 
  File "/Core2-for-AWS-IoT-EduKit/Blinky-Hello-World/utilities/AWS_IoT_registration_helper/registration_helper.py", line 211, in main
    upload_manifest()
  File "/Core2-for-AWS-IoT-EduKit/Blinky-Hello-World/utilities/AWS_IoT_registration_helper/registration_helper.py", line 166, in upload_manifest
    invoke_import_manifest('Default', manifest_data, signer_cert_bytes)
  File "/Core2-for-AWS-IoT-EduKit/Blinky-Hello-World/utilities/AWS_IoT_registration_helper/../trustplatform/TrustnGO/Microchip_manifest_handler.py", line 238, in invoke_import_manifest
    manifest_item = ManifestItem(next(iterator), verification_cert)
  File "/Core2-for-AWS-IoT-EduKit/Blinky-Hello-World/utilities/AWS_IoT_registration_helper/../trustplatform/TrustnGO/Microchip_manifest_handler.py", line 176, in __init__
    self.run()
  File "/Core2-for-AWS-IoT-EduKit/Blinky-Hello-World/utilities/AWS_IoT_registration_helper/../trustplatform/TrustnGO/Microchip_manifest_handler.py", line 195, in run
    raise ValueError('kid does not match certificate value')
ValueError: kid does not match certificate value

[mstfldmr]

deleting IoT thing and IoT certificate also works