Refactor (#174)

- Goal was to simplify main.go complexity
- Use common structures and interfaces for all vpn providers
- Moved files around
- Removed some alias models

internal/models/alias.go

@@ -7,24 +7,6 @@ type (
 	DNSProvider string
 	// DNSHost is the DNS host to use for TLS validation
 	DNSHost string
-	// PIAEncryption defines the level of encryption for communication with PIA servers
-	PIAEncryption string
-	// PIARegion is used to define the list of regions available for PIA
-	PIARegion string
-	// MullvadCountry is used as the country for a Mullvad server
-	MullvadCountry string
-	// MullvadCity is used as the city for a Mullvad server
-	MullvadCity string
-	// MullvadProvider is used as the Internet service provider for a Mullvad server
-	MullvadProvider string
-	// WindscribeCity is used as the region for a Windscribe server
-	WindscribeRegion string
-	// SurfsharkRegion is used as the region for a Surfshark server
-	SurfsharkRegion string
-	// CyberghostRegion is the country name for a Cyberghost server
-	CyberghostRegion string
-	// CyberghostGroup is the server group for a Cyberghost server
-	CyberghostGroup string
 	// URL is an HTTP(s) URL address
 	URL string
 	// Filepath is a local filesytem file path
@@ -32,7 +14,7 @@ type (
 	// TinyProxyLogLevel is the log level for TinyProxy
 	TinyProxyLogLevel string
 	// VPNProvider is the name of the VPN provider to be used
-	VPNProvider string
+	VPNProvider string // TODO
 	// NetworkProtocol contains the network protocol to be used to communicate with the VPN servers
 	NetworkProtocol string
 )