* Load tracing filter only from config and simplify logic.
* Configure the state storage in the config, not an environment variable.
This also changes the config so that the path is always set rather than being
optional, because Zebra always needs a place to store its config.
* Add skeleton of eventual zebra book
* reorg sections
* restore file and reorg book a little
* try setting up a firebase deployment
* allow firebase ci to work on test
* download mdbook
* fix book path
* use newer version of mdbook
* remove event hook for book branch pre merge
* Apply suggestions from code review
Co-authored-by: Henry de Valence <hdevalence@hdevalence.ca>
Co-authored-by: Henry de Valence <hdevalence@hdevalence.ca>