PHPCS fixes and UI changes

config/schema/rest_api_authentication.schema.yml

css/rest_api_authentication.basic_style_settings.css

css/rest_api_authentication.style_settings.css

rest_api_authentication.routing.yml

src/AdvancedSettingsForm.php

src/Controller/RestApiAuthenticationController.php

src/CustomerSetupForm.php

src/Form/MiniOrangeAPIAuth.php

src/Form/MiniornageAPIAuthnRequestSupport.php

src/Form/MiniornageAPIAuthnRequestTrial.php

src/MiniorangeApiAuthSupport.php

src/MiniorangeRestAPICustomer.php

src/MoHeadlessIntegration.php

src/RequestForDemoForm.php

src/SetupAuthenticationForm.php

src/UpgradePlansForm.php

src/Utilities.php