We might want to prune the repo from within the library or
the command line and may not be in a privileged context, so
we'll need to jump through the system helper to prune the refs.
Closes: #1034
Approved by: alexlarsson
We download the summary and send it to the system helper, it verifies
the checksum and applies the changes, with the same polkit permissions
required as for an app update (i.e. typically none).
This allows us to update metadata automatically, without permission
requests.
If the bundle contains an origin link we can now install related
things from it, such as locale data.
You can also build the bundle with --runtime-repo=URL, where the url
points to a flatpakrepo file for a repo with runtimes. This works
similar to the RuntimeRepo= feature in flatpakref files.
This lets any client, possibly in a sandbox if it has access to the
session helper, spawn a process on the host, outside any sandbox.
Clearly this is not something you typically want a sandboxed app to
do. However, it is sometimes very useful when using flatpak mainly
for distribution. For instance, an IDE needs to use this to launch a
flatpak build operation inside the sandbox. (Because otherwise recursive
calls to flatpak will not work.)
