feat: api key authentication (#291)

Co-authored-by: Elias Schneider <login@eliasschneider.com>

backend/internal/dto/pagination_dto.go

@@ -0,0 +1,10 @@
+package dto
+
+import "github.com/pocket-id/pocket-id/backend/internal/utils"
+
+type Pagination = utils.PaginationResponse
+
+type Paginated[T any] struct {
+	Data       []T        `json:"data"`
+	Pagination Pagination `json:"pagination"`
+}