Collections, similarly to packages, have a `build.yaml` and
a `finalize.yaml` that are templated for each package.
They have a `collection.yaml` containing a list of
packages that are part of the tree.
Fixes races conditions and make the DB Switchable. Also prepare inside
the CompilationSpec the tree of the deps to be built, and parallelize
only the building jobs.
Closes#7
Signed-off-by: Ettore Di Giacinto <mudler@gentoo.org>
Whenever we update the tree with new informations, all the sibilings
needs to be updated as well
Also switch to inmemory db for recipe - even if this should be a switch
