[frontend] Add events metrics to being sent through RabbitMQ

We need to send the information about events happening in the system and
store them as a timeserie in InfluxDB. We send the data as messages
through RabbitMQ

Co-authored-by: Ana María Martínez Gómez <ammartinez@suse.de>
Co-authored-by: Björn Geuken <bgeuken@suse.de>
Co-authored-by: Christian Bruckmayer <cbruckmayer@suse.com>
Co-authored-by: David Kang <dkang@suse.com>
Co-authored-by: Eduardo Navarro <enavarro@suse.com>