`recalculateAllPossibleTarget` is now a private member of
PipelineManager This was done since all calls that can trigger a change
in the target list have been isolated and the call is done implicitly.
This removes rp_manager_recompute_all_available_targets from PipelineC,
since it was added as a stopgap until the above was implemented.
This commit adds the newly implemented functionality in PipelineC both
in revng.api and the graphql api, allowing:
* retrieval of global variable names
* unwrapping of a single target
* execution of analyses