Add new metric to collect the number of errors found when connecting to the
fail2ban server socket. Errors are split into two categories: connection
errors (e.g. socket file not found), and request errors (e.g. invalid
response received from server).
Update the `up` metric to return `0` if the socket connection fails.
Improve error logging.
Update the code collecting metrics to open a new socket connection each
time metrics are collected. This ensures that a new socket connection is
used each time and avoids errors caused by fail2ban being restarted.
Add new metric to track the total number of jails configured in fail2ban.
Add new metrics for the current and total number of filter failures for
each jail, as well as the current/total number of banned IPs per jail.
The new metrics are collected by sending the `status [jail]` command to the
fail2ban server and parsing the response data.
Add support for connecting the exporter directly to the fail2ban server's
socket to send requests and receive data. The path to the socket file is
optional and specified on startup.
Export a new metric based on the response of the `ping` command sent to the
fail2ban server. The metric is set to 1 if the server responds with `pong`
and 0 in any other case. This metric is only shown if the path to the
socket file was provided on startup.
