Overhaul stats: add TYPE and HELP to Prometheus export#1559

josecelano merged 12 commits intotorrust:developtorrust/torrust-tracker:developfrom

josecelano:1514-overhaul-stats-add-type-and-help-to-prometheus-exportjosecelano/torrust-tracker:1514-overhaul-stats-add-type-and-help-to-prometheus-exportCopy head branch name to clipboard