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

src/tests/_support/Models/ExampleModel.php

@@ -1,26 +0,0 @@
-<?php namespace Tests\Support\Models;
-
-use CodeIgniter\Model;
-
-class ExampleModel extends Model
-{
-	protected $table      = 'factories';
-	protected $primaryKey = 'id';
-
-	protected $returnType     = 'object';
-	protected $useSoftDeletes = false;
-
-	protected $allowedFields = [
-		'name',
-		'uid',
-		'class',
-		'icon',
-		'summary',
-	];
-
-	protected $useTimestamps = true;
-
-	protected $validationRules    = [];
-	protected $validationMessages = [];
-	protected $skipValidation     = false;
-}