PDO plugin: Reflections

* com.noccy.pdo: Implemented reflection for PDO databases,
  tables and columns. Reflectors for MySQL and Sqlite.
* com.noccy.pdo: Added pdo:inspect command.
* com.noccy.docker: Added basic stack management and commands.
* com.noccy.docker: Moved commands to dedicated namespace.
* Environment: readConfig and writeConfig helper added, with
  a flag to use the global config dir ~/.config/spark.

plugins/com.noccy.pdo/PdoResource.php

@@ -4,6 +4,9 @@ namespace SparkPlug\Com\Noccy\Pdo;
 
 use Spark\Resource\ResourceType;
 use PDO;
+use SparkPlug\Com\Noccy\Pdo\Reflection\Reflector\MysqlReflector;
+use SparkPlug\Com\Noccy\Pdo\Reflection\Reflector\ReflectorInterface;
+use SparkPlug\Com\Noccy\Pdo\Reflection\Reflector\SqliteReflector;
 
 class PdoResource extends ResourceType
 {
@@ -47,6 +50,23 @@ class PdoResource extends ResourceType
         return $this->pdo;
     }
 
+    public function getReflector(): ?ReflectorInterface
+    {
+        $uri = $this->options['uri'];
+        
+        if (!preg_match('|^(.+?):|', $uri, $m)) {
+            fprintf(STDERR, "error: Bad resource URI\n");
+            return null;
+        }
+        switch ($m[1]) {
+            case 'mysql':
+                return new MysqlReflector($this);
+            case 'sqlite':
+                return new SqliteReflector($this);
+        }
+
+    }
+
     public function info()
     {
         return $this->options['uri'];