Applications using libflatpak currently have to duplicate the CLI's
private cleanup logic to offer the equivalent of uninstall --delete-data.
Add a standalone API that removes ~/.var/app data and resets permission
store entries without requiring the app to be installed. Keep it separate
from transactions so callers can retry partial failures or reset data for
an installed app.
Validate app IDs before constructing paths, propagate cancellation and
permission table errors, and document partial failure behavior.
Previously, there were three different DTDs used. Let's switch to a single one.
We will go with 4.5, since it is latest version that does not have any backwards incompatible changes.
Razze