PLT-2258 Unified login screen and related APIs (#2820)

* Unified login screen and related APIs

* Refactored login API call to be less convoluted

* Removed LDAP login prompt from invite process

* Fixed existing LDAP users being able to log in if LDAP was configured, but disabled

* Gofmt

* Future proofed login API

* Updated login APIs based on feedback

* Added additional auditing to login API

* Actually removed loginById

webapp/stores/user_store.jsx

@@ -6,7 +6,6 @@ import EventEmitter from 'events';
 
 import Constants from 'utils/constants.jsx';
 const ActionTypes = Constants.ActionTypes;
-import BrowserStore from './browser_store.jsx';
 
 const CHANGE_EVENT = 'change';
 const CHANGE_EVENT_SESSIONS = 'change_sessions';
@@ -97,22 +96,6 @@ class UserStoreClass extends EventEmitter {
         return null;
     }
 
-    getLastEmail() {
-        return BrowserStore.getGlobalItem('last_email', '');
-    }
-
-    setLastEmail(email) {
-        BrowserStore.setGlobalItem('last_email', email);
-    }
-
-    getLastUsername() {
-        return BrowserStore.getGlobalItem('last_username', '');
-    }
-
-    setLastUsername(username) {
-        BrowserStore.setGlobalItem('last_username', username);
-    }
-
     hasProfile(userId) {
         return this.getProfiles()[userId] != null;
     }