feat(template): add multi page upload capability

pkg/svg/templates.go

@@ -1,11 +1,33 @@
 package svg
 
+import "slices"
+
 const KeyRegex string = `\{\{\s*(.*?)\s*\}\}`
 
 type TemplateData struct {
-	Id           string
-	Name         string
+	Id    string
+	Name  string
+	Pages []TemplatePage
+}
+
+type TemplatePage struct {
+	TemplateId   string
+	Page         int
 	TemplateKeys []string
 }
 
 var Storage SvgStorage
+
+func (d TemplateData) AllKeys() []string {
+	keys := make([]string, 0)
+
+	for _, page := range d.Pages {
+		for _, key := range page.TemplateKeys {
+			if !slices.Contains(keys, key) {
+				keys = append(keys, key)
+			}
+		}
+	}
+
+	return keys
+}