tech name must only appear, but not be identical to generator
carrier. This allows to use the name "offshore" for both "offshore-ac"
and "offshore-dc", but then "solar" also catches "solar thermal",
which is fine since for solar thermal potentials are np.inf, unless
limit is 0 since np.inf*0 is nan.
Remove non-renewable generator and storage units from electricity-only
base network, since they're added differently here with links.
Remove unncessary cruft from config.yaml which is not used by
PyPSA-Eur-Sec (e.g. renewable configuration parameters).
Rename "naptha" to correct "naphtha".
