feat(login): add login authentication and authorization (#122)

Add login basic authentication, oauth2 authentication, two factor
authentication and authorization and allow to reset password on expiry.

Fixes #117, #118, #119, #120

src/app/login/login-form/login-form.component.ts

@@ -0,0 +1,56 @@
+import { Component, OnInit } from '@angular/core';
+import { FormGroup, FormBuilder, Validators } from '@angular/forms';
+
+import { finalize } from 'rxjs/operators';
+
+import { Logger, AuthenticationService } from '../../core';
+
+const log = new Logger('Login');
+
+@Component({
+  selector: 'mifosx-login-form',
+  templateUrl: './login-form.component.html',
+  styleUrls: ['./login-form.component.scss']
+})
+export class LoginFormComponent implements OnInit {
+
+  loginForm: FormGroup;
+  passwordInputType: string;
+  error: string;
+  loading = false;
+  authenticationEvent: any;
+
+  constructor(private formBuilder: FormBuilder,
+              private authenticationService: AuthenticationService) {  }
+
+  ngOnInit() {
+    this.createLoginForm();
+    this.passwordInputType = 'password';
+  }
+
+  public login() {
+    this.loading = true;
+    this.loginForm.disable();
+    this.authenticationService.login(this.loginForm.value)
+      .pipe(finalize(() => {
+        this.loginForm.reset();
+        this.loginForm.markAsPristine();
+        // Bug: Validation errors won't get removed on reset
+        this.loginForm.enable();
+        this.loading = false;
+      })).subscribe();
+  }
+
+  public forgotPassword() {
+    console.log('TODO: Forgot Password');
+  }
+
+  private createLoginForm() {
+    this.loginForm = this.formBuilder.group({
+      'username': ['', Validators.required],
+      'password': ['', Validators.required],
+      'remember': false
+    });
+  }
+
+}