Silverstripe Login-form Branding

Replaces/reduces the default Silverstripe branding of the login forms module and makes it easily configurable.

The icon above- and credits below the form are configurable via Yaml:

Restruct\SilverStripe\AdminBranding\SecurityBrandingExtension:
  built_by: 'Built by <a href="https://yoursite.tld" target="_blank">Your Company</a>'
  powered_by: 'Powered by <a href="https://silverstripe.org" target="_blank">Silverstripe</a>'
  include_icon: true

Add your (client’s) logo/brand above the form

Add an AppBrand.ss template file in either [app]/templates/Includes/ or themes/[client-theme]/templates/Includes/, eg:

<h1 class="app-brand__logo">AppBrand</h1>

And set the theme as highest prio on SilverStripe\LoginForms\EnablerExtension (before #admin-branding):

---
Before:
  - '#admin-branding'
---
SilverStripe\LoginForms\EnablerExtension:
  login_themes:
    - 'client-theme'

Optionally set Restruct\SilverStripe\AdminBranding\SecurityBrandingExtension.include_icon to false to remove the icon.

Shield-lock icon kindly provided by Bootstrap Icons.