Make the installation process shorter by condensing it into one step.
Right now it takes 2-4 steps to set up the application, excluding MySQL, Nginx, TLS certificate, and Systemd setup. We should simplify the application install (everything else is out of scope for this task).
Create new writefreely --install command. This should replace --config, --init-db, and --gen-keys steps. Notes:
- We should assume that the configured database already exists -- the CREATE DATABASE step will now need to happen before install.
- We might want to prompt user for keys dir location during configuration, since they won't have a chance to change that config value before --gen-keys is run.
- Pro: save some steps (update config file, move keys dir)
- Con: slightly complicates install process for average person that isn't too concerned about location