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/phpunit.xml.dist

@@ -1,60 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<phpunit bootstrap="vendor/codeigniter4/framework/system/Test/bootstrap.php"
-		backupGlobals="false"
-		colors="true"
-		convertErrorsToExceptions="true"
-		convertNoticesToExceptions="true"
-		convertWarningsToExceptions="true"
-		stopOnError="false"
-		stopOnFailure="false"
-		stopOnIncomplete="false"
-		stopOnSkipped="false">
-	<testsuites>
-		<testsuite name="app">
-			<directory>./tests</directory>
-		</testsuite>
-	</testsuites>
-
-	<filter>
-		<whitelist addUncoveredFilesFromWhitelist="true" processUncoveredFilesFromWhitelist="true">
-			<directory suffix=".php">./app</directory>
-			<exclude>
-				<directory suffix=".php">./app/Views</directory>
-				<file>./app/Config/Routes.php</file>
-			</exclude>
-		</whitelist>
-	</filter>
-
-	<logging>
-		<log type="coverage-html" target="build/logs/html"/>
-		<log type="coverage-clover" target="build/logs/clover.xml"/>
-		<log type="coverage-php" target="build/logs/coverage.serialized"/>
-		<log type="coverage-text" target="php://stdout" showUncoveredFiles="false"/>
-		<log type="testdox-html" target="build/logs/testdox.html"/>
-		<log type="testdox-text" target="build/logs/testdox.txt"/>
-		<log type="junit" target="build/logs/logfile.xml"/>
-	</logging>
-
-	<php>
-		<server name="app.baseURL" value="http://example.com"/>
-
-		<!-- Directory containing phpunit.xml -->
-		<const name="HOMEPATH" value="./"/>
-
-		<!-- Directory containing the Paths config file -->
-		<const name="CONFIGPATH" value="./app/Config/"/>
-
-		<!-- Directory containing the front controller (index.php) -->
-		<const name="PUBLICPATH" value="./public/"/>
-
-		<!-- Database configuration -->
-<!--	<env name="database.tests.hostname" value="localhost"/>  -->
-<!--	<env name="database.tests.database" value="tests"/>	     -->
-<!--	<env name="database.tests.username" value="tests_user"/> -->
-<!--	<env name="database.tests.password" value=""/>		     -->
-<!--	<env name="database.tests.DBDriver" value="MySQLi"/>	 -->
-<!--	<env name="database.tests.DBPrefix" value="tests_"/>	 -->
-		<env name="database.tests.database" value=":memory:"/>
-		<env name="database.tests.DBDriver" value="SQLite3"/>
-	</php>
-</phpunit>