fead: expand archive options

add an option to select how to archive the entries
add an option for what entries to archive
change the concurrentcy limit to a semaphore instead of a ticker

internal/service/service.go

@@ -1,6 +1,8 @@
 package service
 
-import "fmt"
+import (
+	"fmt"
+)
 
 type ServiceOption string
 
@@ -8,11 +10,21 @@ const (
 	ServiceLinkding ServiceOption = "linkding"
 )
 
+type ServiceArchiveMethod string
+
+const (
+	ServiceArchiveMethodSeen    = "seen"
+	ServiceArchiveMethodArchive = "archive"
+	ServiceArchiveMethodBoth    = "both"
+)
+
 type ServiceConfig struct {
-	Service ServiceOption
-	Host    string
-	User    string
-	Token   string
+	Service     ServiceOption
+	Host        string
+	User        string
+	Token       string
+	Method      ServiceArchiveMethod
+	MaxRequests uint8
 }
 
 type Service interface {