Allows obtaining the 'Origin' property from the cached InRelease file.
Used the once_cell crate for the config module, because it is already
used in proxmox-backup and seemed to be the right fit here.
For now, the config module is just used to be able to override the
path for the test environment, but those are actual APT config
variables, and in the future, it can be extended and used to actually
parse the apt.conf(.d/*) on the system.
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
Get handles for the available repositories along with their current
configuration status and make it possible to add them.
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
