[PROD] Image upload for emergency summary

[szabozoltan69]

Issue

Recently the image copying+pasting is a tempting workflow for putting images into emergency summary.
It strongly slows down the service (even can cause a blackout).

We should provide a possibility which is similar to the snippet file uploads (to the same blob storage!) near the summary.
[Snippet upload is not good for this purpose, because those images appear on a tab of the emergency]

If we work with this, maybe that is a to-be-solved also in one deployment: #1624
Relates to #2460 also (as a quick solution for that).