Evaluate VICI as data source

Currently, the ipsec_exporter uses the output of the ipsec statusall command. This was a quick and easy way to get the exporter working.

As far as I understand the ipsec command uses the VICI protocol to communicate with the daemon. If this is true this could

make the data collection and general exporter architecture much cleaner, stable and easier to extend
allow us to run the exporter as an unprivileged user without sudo (making #27 obsolete by the cleaner data collection approach)
allow us to run the exporter in a Docker Container (effectively making #24 possible)
this might also address issues like #16 & #17
this might make issues like #29 & #32 much more straight forward to implement (as we would not rely on parsing cmd output anymore)

dennisstritzke / ipsec_exporter