Geo: Replication slots to turn red when it's less than 100%

Proposal

When there is a configured yet unused replication slot PostgreSQL saves up the WAL logs for this slot. If left for an extended period of time these WAL logs can saturate the storage on the host machine. A configured and unused WAL slot should be an error state therefore, if WAL slots on the UI is < 100% we should change the colour of the bar to red to highlight to the systems admin that there is a problem with the configuration.