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.
Read the response data from the socket in chunks to prevent errors when
processing large payloads. The initial implementation solved large payloads
by just defining a very large buffer, but this is not a solution. The new
code reads the socket data in a loop until a terminator is found and
appends all the data into a single byte array.
Reduce the buffer size to `1024` bytes.
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.
