Setup SAML signout

[ermsdev]

shared-ng/config.ts

Line 4 in 507eee8

export const SAML_LOGOUT_URL = SAML_URL + '/?slo&redirect=';

We were preparing to implement sign in and out with ASWWU's saml server but never completed it. The sign out variable (and possibly the sign in variable) isn't used anywhere in the project as of writing this issue, but the code does have a purpose, so don't delete it just because it's unused!