add spinner to the signin button to indicate progress

app/components/button/sign_in.hbs

+{{#if @disabled}}
+  <button
+    class="btn btn-block btn-primary btn-lg w-100"
+    disabled
+    type="submit">Sign In</button>
+{{else}}
+  <button
+    class="btn btn-block btn-primary btn-lg w-100"
+    type="submit"
+    {{on "click" @onSubmit}}>
+      <Spinner @inProgress={{@inProgress}} />
+      Sign In
+  </button>
+{{/if}}
\ No newline at end of file

app/components/login/index.hbs

@@ -16,17 +16,12 @@
       <label for="password" class="form-label">Password</label>
   </div>
 
-  {{#if this.disabled}}
-  <button
-    class="btn btn-block btn-primary btn-lg w-100"
-    disabled
-    type="submit">Sign In</button>
-  {{else}}
-    <button
-    class="btn btn-block btn-primary btn-lg w-100"
-    type="submit"
-    {{on "click" this.onSubmit}}>Sign In</button>
-  {{/if}}
+  <Button::SignIn
+    @disabled={{this.disabled}}
+    @onSubmit={{this.onSubmit}}
+    @inProgress={{@inProgress}}>
+  </Button::SignIn>
+
   <div class="mt-3">
     <input type="checkbox" id="remember" name="remember">
     <label class="font-weight-normal my-2" for="remember">

app/components/spinner.hbs

+<span
+  class="spinner-border spinner-border-sm {{if @inProgress 'visible' 'invisible'}}"
+  role="status"
+  aria-hidden="true">
+</span>
\ No newline at end of file

app/controllers/login.js

@@ -7,12 +7,14 @@ import { base_url } from 'papermerge/utils';
 
 export default class LoginController extends Controller {
   @tracked errorMessage;
+  @tracked in_progress = false;
   @service session;
   @service router;
 
   @action
   async authenticate(username, password) {
     try {
+      this.in_progress = true;
       await this.session.authenticate(
         'authenticator:auth-token',
         username,
@@ -27,6 +29,8 @@ export default class LoginController extends Controller {
       } else {
         this.errorMessage = error;
       }
+    } finally {
+      this.in_progress = false;
     }
 
     if (this.session.isAuthenticated) {
@@ -34,4 +38,8 @@ export default class LoginController extends Controller {
       this.router.transitionTo('authenticated.index');
     }
   }
+
+  get inProgress() {
+    return this.in_progress;
+  }
 }

app/templates/login.hbs

@@ -11,7 +11,9 @@
           Please sign in to start your session
         </p>
 
-        <Login @onSubmit={{this.authenticate}}>
+        <Login
+          @onSubmit={{this.authenticate}}
+          @inProgress={{this.inProgress}}>
           {{#if this.errorMessage}}
             <p class="text-danger">{{this.errorMessage}}</p>
           {{/if}}