Add a new startup option to exit the exporter when an error occurs when connecting to the fail2ban socket file.
This option is set to "false" by default.
Update the exporter logging on startup to include the exporter version,
the path to the fail2ban socket, and whether basic-auth is enabled or not.
Fix code printing error messages on invalid CLI parameters to correct line
breaks and correctly print the "usage" information.
Remove all database-based metrics from the metrics endpoint.
Remove all code related to pulling metrics from the fail2ban database.
Remove all configuration variables related to the fail2ban database.
The CLI parameter for the database path was not removed to avoid breaking
compatibility.
Update docker entrypoint to remove references to the fail2ban database.
Remove all references to the old database metrics from the README.
Create a new `collector` folder to store the code for the different
collectors. Move the existing f2b and textfile collectors to this folder.
Minor refactors to the f2b collector to better match the code style of the
newer textfile collector.
