Remove or update startup-flow.png

hedera-app contains a file startup-flow.png which is now out of date. It can probably just be removed, but may be referenced in the package-info.java file. That file should also be updated or removed or the image can be updated. But it should be accurate.

Start in hedera-app by locating startup-flow.png and checking package-info.java for references to it. Determine whether the image or its reference should be removed or updated, and verify that the remaining documentation is accurate and contains no stale reference.

Written by the indexing model from the issue text.