♻️ Refactoriza página de bienvenida y tema Basic

- Actualiza `Welcome` para usar el nuevo componente `Intro`.
- Simplifica el tema `Basic` apoyándose en la lógica de `Theme`.
- Predefine los *assets* básicos como recursos de `Theme`.
- Refactoriza archivos de localicación para reflejar los cambios de los
componentes.

src/locale/en-US/welcome.ftl

@@ -1,16 +1,12 @@
 welcome_extension_name = Default Homepage
 welcome_extension_description = Displays a default homepage when none is configured.
 
-welcome_page = Welcome page
-welcome_title = Hello, world!
-
-welcome_intro = Discover⚡{ $app }
-welcome_powered = A web solution powered by <strong>PageTop</strong>
+welcome_title = Welcome page
 
 welcome_status_title = Status
 welcome_status_1 = If you can see this page, it means the <strong>PageTop</strong> server is running correctly, but the application is not fully configured. This may be due to routine maintenance or a temporary issue.
 welcome_status_2 = If the issue persists, please <strong>contact the system administrator</strong>.
 
 welcome_support_title = Support
-welcome_support_1 = To report issues with the <strong>PageTop</strong> framework, use <a href="https://git.cillero.es/manuelcillero/pagetop/issues" target="_blank" rel="noreferrer">SoloGit</a>. Remember, before opening a new issue, review the existing ones to avoid duplicates.
+welcome_support_1 = To report issues with the <strong>PageTop</strong> framework, use <a href="https://github.com/manuelcillero/pagetop/issues" target="_blank" rel="noreferrer">GitHub</a>. Remember, before opening a new issue, review the existing ones to avoid duplicates.
 welcome_support_2 = For issues specific to the application (<strong>{ $app }</strong>), please use its official repository or support channel.