* o/snapstate: store unlinked component information in change
As we will need this information in the component discard task.
* o/snapstate: discard previous component on a component refresh
Only one can be installed in the system at the same time.
* tests/component: check removal of older component after refresh
* o/snapstate: add function to retrieve component setup
Add function to find ComponentSetup for a task that is part of the
tasks created to do a component operation.
* o/snapstate: store unlinked component in ComponentSetup
* o/snapstate/backend: remove component related directories if empty
* o/snapstate: use SnapSetup to store the previous kernel revision
instead of having an object directly in the change.
* o/snapstate: store unlinked component in setup task
* o/snapstate: set previous kernel in setup task
instead of making it part of SnapSetup.
* o/snapstate: some additional tests
* daemon: support sideloading of components
* o/snapstate: check info in snap and component is coherent
Make sure that when we install a component it has been defined by the
owner snap and that the type is coherent betwee snap and component
metadata.
* cmd/snap: allow installation of local components
* tests/main: add spread test for components
* daemon: add component name to API data
* fixup! o/snapstate: check info in snap and component is coherent
* fixup! cmd/snap: allow installation of local components
* fixup! daemon: support sideloading of components
* fixup! tests/main: add spread test for components
* daemon: add helper for ErrorKindSnapNotInstalled errors
* fixup! daemon: support sideloading of components
