Add new login layouts and other login settings, resolves #1055

[berthob98]

Description

This PR introduces two new login layouts tabs and accordion along with a new login background layout option, allowing users to switch between the default layout and a split-screen layout. Additionally, it adds settings to control various aspects of the login page, including the login container width, the login texts, and the option to disable individual login methods. Resolves #1055

Example layouts:

• Tabs with default background:

• Accordion with split-screen background:

Added Settings:

1. Login container width Controls the width of the login container (default: 500px) logincontainerwidth

2. Login layout Choose between vertical, tabs, or accordion layout loginlayout

3. Login background layout Choose between default or split screen layout loginbackgroundlayout

4. Primary login Specify which login method should be active by default in tabs/accordion layouts primarylogin

5. Local login intro text Customize the intro text for local login loginlocalintrotext

6. Local login tab text Customize the tab text for local login (tabs layout only) loginlocallogintabtext

7. IDP login Control if IDP login buttons are shown loginidploginenable

8. IDP login intro text Customize the intro text for IDP login loginidpintrotext

9. IDP login tab text Customize the tab text for IDP login (tabs layout only) loginidplogintabtext

10. Self registration Control if self registration is shown loginselfregistrationenable

11. Self registration intro Control if intro text is shown for self registration loginselfregistrationshowintro

12. Self registration intro text Customize the intro text for self registration loginselfregistrationintrotext

13. Self registration tab text Customize the tab text for self registration (tabs layout only) loginselfregistrationlogintabtext

14. Guest login Control if guest login is shown loginguestloginenable

15. Guest login intro Control if intro text is shown for guest login loginguestshowintro

16. Guest login intro text Customize the intro text for guest login loginguestintrotext

17. Guest login tab text Customize the tab text for guest login (tabs layout only) loginguestlogintabtext

Technical changes:

The code in this PR prepares the loginmethods inside core_renderer.php and iterates over these methods inside the loginform.mustache. This ensures that the login methods are rendered in the preferred order in the HTML DOM. As a result, Bootstrap nav-tabs and accordion classes can be easily applied.

Inside loginform.mustache, the flags loginaccordion, loginbackgroundlayoutdefault, and logintabs are used to conditionally render the appropriate elements for the different layouts.

The split-screen layout is implemented via CSS by applying a new class: login-background-layout-splitscreen.