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/params/cyberghost.go

@@ -1,25 +1,22 @@
 package params
 
 import (
-	"strings"
-
 	libparams "github.com/qdm12/golibs/params"
 	"github.com/qdm12/private-internet-access-docker/internal/constants"
-	"github.com/qdm12/private-internet-access-docker/internal/models"
 )
 
 // GetCyberghostGroup obtains the server group for the Cyberghost server from the
 // environment variable CYBERGHOST_GROUP
-func (p *reader) GetCyberghostGroup() (region models.CyberghostGroup, err error) {
+func (p *reader) GetCyberghostGroup() (group string, err error) {
 	s, err := p.envParams.GetValueIfInside("CYBERGHOST_GROUP", constants.CyberghostGroupChoices())
-	return models.CyberghostGroup(strings.ToLower(s)), err
+	return s, err
 }
 
 // GetCyberghostRegion obtains the country name for the Cyberghost server from the
 // environment variable REGION
-func (p *reader) GetCyberghostRegion() (region models.CyberghostRegion, err error) {
+func (p *reader) GetCyberghostRegion() (region string, err error) {
 	s, err := p.envParams.GetValueIfInside("REGION", constants.CyberghostRegionChoices())
-	return models.CyberghostRegion(strings.ToLower(s)), err
+	return s, err
 }
 
 // GetCyberghostClientKey obtains the one line client key to use for openvpn from the