Extend configuration for volume and other preferences

[mloskot]

It would be a useful feature if the current Config

RadioGoGo/config/config.go

Lines 29 to 37 in c86c8ac

	type Config struct {
	Theme struct {
	TextColor string `yaml:"textColor"`
	PrimaryColor string `yaml:"primaryColor"`
	SecondaryColor string `yaml:"secondaryColor"`
	TertiaryColor string `yaml:"tertiaryColor"`
	ErrorColor string `yaml:"errorColor"`
	}
	}

was extended beyond just theming and allow users to pre-set the player with things like

• preferred volume %
• enable/disable hiding of broken stations, related to Hide & report broken stations #2
• list favourite stations, could be part of Bookmark stations #7
• preferred sorting by country, language, votes - a new feature needed
• filter unwanted countries, tags - a new feature needed