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/Reflection/Reflector/MysqlTableReflection.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace SparkPlug\Com\Noccy\Pdo\Reflection\Reflector;
+
+use PDO;
+use SparkPlug\Com\Noccy\Pdo\PdoResource;
+use SparkPlug\Com\Noccy\Pdo\Reflection\ColumnReflectionInterface;
+use SparkPlug\Com\Noccy\Pdo\Reflection\TableReflectionInterface;
+
+class MysqlTableReflection implements TableReflectionInterface
+{
+    private PDO $pdo;
+
+    private string $table;
+
+    private array $columns = [];
+
+    public function __construct(PdoResource $db, string $table)
+    {
+        $pdo = $db->getPDO();
+
+        $columnQuery = $pdo->prepare('show fields from '.$table);
+        $columnQuery->execute();
+        $columns = $columnQuery->fetchAll(PDO::FETCH_ASSOC);
+
+        foreach ($columns as $column) {
+            $name = $column['Field'];
+            $this->columns[$name] = new MysqlColumnReflection($db, $column);
+        }
+
+        /*
+
+        SELECT table_schema, table_name, column_name, ordinal_position, data_type, 
+            numeric_precision, column_type, column_default, is_nullable, column_comment 
+            FROM information_schema.columns 
+            WHERE (table_schema='schema_name' and table_name = 'table_name')
+            order by ordinal_position;
+
+            OR
+
+            show fields from 'table_name' 
+        */
+    }
+
+    public function getAllColumns(): array
+    {
+        return $this->columns;
+    }
+
+    public function getColumn(string $name): ?ColumnReflectionInterface
+    {
+        return $this->columns[$name] ?? null;
+    }
+
+}
+