chore(all): memory and thread safe storage

- settings: get filter choices from storage for settings validation
- updater: update servers to the storage
- storage: minimal deep copying and data duplication
- storage: add merged servers mutex for thread safety
- connection: filter servers in storage
- formatter: format servers to Markdown in storage
- PIA: get server by name from storage directly
- Updater: get servers count from storage directly
- Updater: equality check done in storage, fix #882

internal/vpn/state/state.go

@@ -5,23 +5,18 @@ import (
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/loopstate"
-	"github.com/qdm12/gluetun/internal/models"
 )
 
 var _ Manager = (*State)(nil)
 
 type Manager interface {
 	SettingsGetSetter
-	ServersGetterSetter
-	GetSettingsAndServers() (vpn settings.VPN, allServers models.AllServers)
 }
 
-func New(statusApplier loopstate.Applier,
-	vpn settings.VPN, allServers models.AllServers) *State {
+func New(statusApplier loopstate.Applier, vpn settings.VPN) *State {
 	return &State{
 		statusApplier: statusApplier,
 		vpn:           vpn,
-		allServers:    allServers,
 	}
 }
 
@@ -30,18 +25,4 @@ type State struct {
 
 	vpn        settings.VPN
 	settingsMu sync.RWMutex
-
-	allServers   models.AllServers
-	allServersMu sync.RWMutex
-}
-
-func (s *State) GetSettingsAndServers() (vpn settings.VPN,
-	allServers models.AllServers) {
-	s.settingsMu.RLock()
-	s.allServersMu.RLock()
-	vpn = s.vpn
-	allServers = s.allServers
-	s.settingsMu.RUnlock()
-	s.allServersMu.RUnlock()
-	return vpn, allServers
 }