Fheos db path config

[eshelB]

Adding the option to configure fheos' db path via the file or the command-line options (note that fheo's main command still does not parse cmd args or config files, therefore a default configuration is initialized and environment variables are the still only methods to change behaviour).

• The new config field is fheos category under conf (not inside fhenix since that is the config that is going to the warp-drive which does not need to be aware of such things).
• The new inner fields are fheos-db-path and also included fheos-security-zones for the future to make it possible to configure the amount of security zones that are initialized. (This latter, however, can't be used directly right now, since it's accessible from nitro, but nitro does not use it at any point, it is used only via fheo's command line, which does not parse any config but instead only has a default value which can be overriden by the environment varialbe FHEOS_SECURITY_ZONES).

Side effects:

• using this quickfix which I bumped into to build nitro correctly
• the old config file can be used, as the new fields are optional.
• I changed the fheos command to use a new subcommand, init-keys instead of init-state because the latter was creating a db when it was unnecessary, since nitro created it again nevertheless. Now the run.sh uses init-keys instead, which is more pinpointed to do just that. Maybe we need to ping @davidecostantini that run.sh changed for later versions.

monday: 1638809482
nitro: https://github.com/FhenixProtocol/nitro/pull/182