Add team member invite by email (#20307)

Allows to add (not registered) team members by email.

related #5353

Invite by mail:

![grafik](https://user-images.githubusercontent.com/1666336/178154779-adcc547f-c0b7-4a2a-a131-4e41a3d9d3ad.png)

Pending invitations:

![grafik](https://user-images.githubusercontent.com/1666336/178154882-9d739bb8-2b04-46c1-a025-c1f4be26af98.png)

Email:

![grafik](https://user-images.githubusercontent.com/1666336/178164716-f2f90893-7ba6-4a5e-a3db-42538a660258.png)

Join form:

![grafik](https://user-images.githubusercontent.com/1666336/178154840-aaab983a-d922-4414-b01a-9b1a19c5cef7.png)

Co-authored-by: Jack Hay <jjphay@gmail.com>

web_src/js/features/comp/SearchUserBox.js

@@ -3,15 +3,20 @@ import {htmlEscape} from 'escape-goat';
 
 const {appSubUrl} = window.config;
 
+const looksLikeEmailAddressCheck = /^\S+@\S+$/;
+
 export function initCompSearchUserBox() {
   const $searchUserBox = $('#search-user-box');
+  const allowEmailInput = $searchUserBox.attr('data-allow-email') === 'true';
+  const allowEmailDescription = $searchUserBox.attr('data-allow-email-description');
   $searchUserBox.search({
     minCharacters: 2,
     apiSettings: {
       url: `${appSubUrl}/user/search?q={query}`,
       onResponse(response) {
         const items = [];
-        const searchQueryUppercase = $searchUserBox.find('input').val().toUpperCase();
+        const searchQuery = $searchUserBox.find('input').val();
+        const searchQueryUppercase = searchQuery.toUpperCase();
         $.each(response.data, (_i, item) => {
           let title = item.login;
           if (item.full_name && item.full_name.length > 0) {
@@ -28,6 +33,14 @@ export function initCompSearchUserBox() {
           }
         });
 
+        if (allowEmailInput && items.length === 0 && looksLikeEmailAddressCheck.test(searchQuery)) {
+          const resultItem = {
+            title: searchQuery,
+            description: allowEmailDescription
+          };
+          items.push(resultItem);
+        }
+
         return {results: items};
       }
     },

web_src/less/_organization.less

@@ -119,6 +119,11 @@
         margin-top: -3px;
       }
     }
+
+    .ui.avatar {
+      width: 100%;
+      height: 100%;
+    }
   }
 
   &.members {