[Bug] Icon/Screenshot placeholder for applications without one

[arvchristos]

Trying to set up imap-filter-proxy as a servapp (initially for my personal market), I realized that there is no icon placeholder in case none can be provided, as this project does not have a logo. The same applies for the screenshots.

For the screenshot case, I saw that there is at least one application that does not provide any, but provides a .keep file (https://github.com/azukaar/cosmos-servapps-official/tree/master/servapps/unpackerr/screenshots). This results in a broken include for the Cosmos interface:

What is the suggested solution for cases like this?

I think a good idea would be to add a placeholder both for icons and screenshots.

[azukaar]

Something like a simple image with the name of the project can be used as screenshot / logo for example?