fix: autosave wireguard conf files (#303)

* fix: autosave wireguard conf files

- Fix subscription to Interface and Peer updates topics
- Remove admin permissions validation
- Update file on peer deletion
- Change save condition to configured storage path only, as initialized interface is not nil

* Added  comment to peer config for prometheus exporter

internal/app/configfile/tpl_files/wg_interface.tpl

@@ -60,6 +60,8 @@ PostDown = {{ .Interface.PostDown }}
 {{range .Peers}}
 {{- if not .IsDisabled}}
 [Peer]
+{{/* `friendly_name` used by https://github.com/MindFlavor/prometheus_wireguard_exporter */ -}}
+# friendly_name = {{ .DisplayName }}
 # -WGP- Peer: {{.Identifier}}
 # -WGP- Created: {{.CreatedAt}}
 # -WGP- Updated: {{.UpdatedAt}}
@@ -86,4 +88,4 @@ Endpoint = {{ .Endpoint.GetValue }}
 PersistentKeepalive = {{ .PersistentKeepalive.GetValue  }}
 {{- end}}
 {{- end}}
-{{end}}
+{{end}}