Media-service background job to generate missing thumbnails for an organisation

[himeshr]

Is your feature request related to a problem? Please describe.
In several instances to regenerate thumbnails for an org, we need to manually invoke avni-media service with a list of media s3 urls. Ideally, we should have a job, that does this in an automated manner for the specified org.

Describe the solution you'd like
Introduce an media-service job endpoint which can be invoked by an User with Reporting privilege.
This would trigger the regeneration of missing thumbnails for the User's org.

• Find all images in the org
• Filter out those, which already have a thumbnail
• Invoke the job with the list of s3 urls for the remaining entities

Describe alternatives you've considered
Alternatively, continue to do the same manual process to regenerate thumbnails.

Additional context
We might not always be able to generate thumbnails for all the images, due to various reasons, ignore such media.
Ex : #172