Add Project MetaData API calls

app/Api/Procedure/ProjectMetaDataProcedure.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Kanboard\Api\Procedure;
+
+use Kanboard\Api\Authorization\ProjectAuthorization;
+
+/**
+ * Class ProjectMetadataProcedure
+ *
+ * @package Kanboard\Api\Procedure
+ * @author  Frederic Guillot
+ */
+class ProjectMetadataProcedure extends BaseProcedure
+{
+    public function getProjectMetadata($project_id)
+    {
+        ProjectAuthorization::getInstance($this->container)->check($this->getClassName(), 'getProject', $project_id);
+        return (object) $this->projectMetadataModel->getAll($project_id);
+    }
+
+    public function getProjectMetadataByName($project_id, $name)
+    {
+        ProjectAuthorization::getInstance($this->container)->check($this->getClassName(), 'getProject', $project_id);
+        return $this->projectMetadataModel->get($project_id, $name);
+    }
+
+    public function saveProjectMetadata($project_id, array $values)
+    {
+        ProjectAuthorization::getInstance($this->container)->check($this->getClassName(), 'updateProject', $project_id);
+        return $this->projectMetadataModel->save($project_id, $values);
+    }
+
+    public function removeProjectMetadata($project_id, $name)
+    {
+        ProjectAuthorization::getInstance($this->container)->check($this->getClassName(), 'updateProject', $project_id);
+        return $this->projectMetadataModel->remove($project_id, $name);
+    }
+}