Add support for more generic notification

This is a start to have different kinds of notifications. It is
possible to be notified via e-mail, matrix or gotify. It also extends
the current "periodic query" for due items by allowing notification
over different channels. A "generic periodic query" variant is added
as well.

modules/common/src/main/scala/docspell/common/ItemQueryString.scala

@@ -6,6 +6,8 @@
 
 package docspell.common
 
+import io.circe.{Decoder, Encoder}
+
 final case class ItemQueryString(query: String) {
   def isEmpty: Boolean =
     query.isEmpty
@@ -15,4 +17,9 @@ object ItemQueryString {
 
   def apply(qs: Option[String]): ItemQueryString =
     ItemQueryString(qs.getOrElse(""))
+
+  implicit val jsonEncoder: Encoder[ItemQueryString] =
+    Encoder.encodeString.contramap(_.query)
+  implicit val jsonDecoder: Decoder[ItemQueryString] =
+    Decoder.decodeString.map(ItemQueryString.apply)
 }

modules/common/src/main/scala/docspell/common/LenientUri.scala

@@ -103,6 +103,8 @@ case class LenientUri(
     val fragPart = fragment.map(f => s"#$f").getOrElse("")
     s"$schemePart:$authPart$pathPart$queryPart$fragPart"
   }
+  override def toString(): String =
+    asString
 }
 
 object LenientUri {

modules/common/src/main/scala/docspell/common/Logger.scala

@@ -6,8 +6,11 @@
 
 package docspell.common
 
+import java.io.{PrintWriter, StringWriter}
+
 import cats.Applicative
-import cats.effect.Sync
+import cats.effect.{Ref, Sync}
+import cats.implicits._
 import fs2.Stream
 
 import docspell.common.syntax.all._
@@ -42,6 +45,28 @@ trait Logger[F[_]] { self =>
     def error(ex: Throwable)(msg: => String): Stream[F, Unit] =
       Stream.eval(self.error(ex)(msg))
   }
+  def andThen(other: Logger[F])(implicit F: Sync[F]): Logger[F] = {
+    val self = this
+    new Logger[F] {
+      def trace(msg: => String) =
+        self.trace(msg) >> other.trace(msg)
+
+      override def debug(msg: => String) =
+        self.debug(msg) >> other.debug(msg)
+
+      override def info(msg: => String) =
+        self.info(msg) >> other.info(msg)
+
+      override def warn(msg: => String) =
+        self.warn(msg) >> other.warn(msg)
+
+      override def error(ex: Throwable)(msg: => String) =
+        self.error(ex)(msg) >> other.error(ex)(msg)
+
+      override def error(msg: => String) =
+        self.error(msg) >> other.error(msg)
+    }
+  }
 }
 
 object Logger {
@@ -88,4 +113,31 @@ object Logger {
         log.ferror(msg)
     }
 
+  def buffer[F[_]: Sync](): F[(Ref[F, Vector[String]], Logger[F])] =
+    for {
+      buffer <- Ref.of[F, Vector[String]](Vector.empty[String])
+      logger = new Logger[F] {
+        def trace(msg: => String) =
+          buffer.update(_.appended(s"TRACE $msg"))
+
+        def debug(msg: => String) =
+          buffer.update(_.appended(s"DEBUG $msg"))
+
+        def info(msg: => String) =
+          buffer.update(_.appended(s"INFO $msg"))
+
+        def warn(msg: => String) =
+          buffer.update(_.appended(s"WARN $msg"))
+
+        def error(ex: Throwable)(msg: => String) = {
+          val ps = new StringWriter()
+          ex.printStackTrace(new PrintWriter(ps))
+          buffer.update(_.appended(s"ERROR $msg:\n$ps"))
+        }
+
+        def error(msg: => String) =
+          buffer.update(_.appended(s"ERROR $msg"))
+      }
+    } yield (buffer, logger)
+
 }

modules/common/src/main/scala/docspell/common/NotifyDueItemsArgs.scala

@@ -27,7 +27,7 @@ case class NotifyDueItemsArgs(
     daysBack: Option[Int],
     tagsInclude: List[Ident],
     tagsExclude: List[Ident]
-) {}
+)
 
 object NotifyDueItemsArgs {