feat: add npm for js dependencies + move src/ files to root folder

- add node service in docker-compose.yml
- update .devcontainer Dockerfile by adding node, npm and vim
- init package.json for npm with tailwindcss, postcss, commitlint and commitizen as dev dependencies
- update default layout main header and footer
- replace CI's welcome_message.php with home.php listing all podcasts
- add AUTHORS.md file
- add docs folder in which to place castopod's technical documentation

tests/database/ExampleDatabaseTest.php

@@ -0,0 +1,42 @@
+<?php
+
+use Tests\Support\Models\ExampleModel;
+
+class ExampleDatabaseTest extends \Tests\Support\DatabaseTestCase
+{
+	public function setUp(): void
+	{
+		parent::setUp();
+
+		// Extra code to run before each test
+	}
+
+	public function testModelFindAll()
+	{
+		$model = new ExampleModel();
+
+		// Get every row created by ExampleSeeder
+		$objects = $model->findAll();
+
+		// Make sure the count is as expected
+		$this->assertCount(3, $objects);
+	}
+
+	public function testSoftDeleteLeavesRow()
+	{
+		$model = new ExampleModel();
+		$this->setPrivateProperty($model, 'useSoftDeletes', true);
+		$this->setPrivateProperty($model, 'tempUseSoftDeletes', true);
+
+		$object = $model->first();
+		$model->delete($object->id);
+
+		// The model should no longer find it
+		$this->assertNull($model->find($object->id));
+
+		// ... but it should still be in the database
+		$result = $model->builder()->where('id', $object->id)->get()->getResult();
+
+		$this->assertCount(1, $result);
+	}
+}