Color fix for terminal with white background

[Fran-Rg]

Issue

Can't see on light colour background (there are other lines underneath)

https://github.com/quantumsheep/sshs/blob/5e72c291538d100bbbf76c88be8c0c9362860987/ui/hosts.go#L232

Possible resolution

• Option 1: Detect the terminal's font colour and match the same
• Option 2: provide some config option for set of colour templates
• Option 3: force black background