* Update config.default.yaml
Some people find it counterintuitive that battery and H2 storage are not kept from PyPSA-Eur. An explicit mention can help here.
* Update installation.rst
We only use one config.yaml file
* Add an arrow from biomass to carbon dioxide.
This signals that we also have BECCS in the model.
Co-authored-by: martavp <martavictoriaperez@gmail.com>