Fix pivotal logo rendering glitch on login.html

[#68645390]
Choose login page logo based on brand

[#68645390]
Determine brand from the environment in thymeleaf templates

instead of relying on the controller placing it on the model

[#68645390]
Restore the error message on the login page

[#68645390]
Don't show SAML "passcode" prompt in the Login Server UI.

- SAML controller filters out passcode prompt from text/html requests
- Parameterize RestTemplate for testing purposes
- More MockMVC test coverage for RemoteUaaController

[#68645390]
Add link to login with corporate credentials when SAML profile is active.

- Set active profiles from merged config in test context loader

[#68645390]
OSS branding for login page.

[#68645390]