Add better handling for the azure marketplace updates

This commit fixes:
- Add better parsing for the LTS, earlier this was broken and the LTS
  release was not found in the list of supported channels.
- Update the account_name to flatcar0001
- We hitting the 100 limit for the Azure images no on a regular basis
  so added a threshold to remove the images when the number is higher
  than 95
- Add the option to delete the draft versions which is quite difficult
  to do manually as it involves time and effort and the script works
  a bit differently where it handles channel across plans where if any
  thing needs to rectified then all the plans needs to be visited and
  handled manually. The commit eases the process a bit
- Add a dry run mode to check if everything will be well run
- Formatting using black

Signed-off-by: Sayan Chowdhury <sayan.chowdhury2012@gmail.com>

Author: sayanchowdhury