Specify project name in settings.gradle

This way we don't have to clone into a 'spring-security-saml' directory
if we wish to build and install. As this way we overrid the project name
via `rootProject.name`.

Later if we want to change this to a multi-project build - i.e. with an
app to use for quick testing (like in spring security core) - then we
can change to something like:

    findProject(':plugin').name = 'spring-security-saml'

settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'spring-security-saml'