feat: Read-only users (#1955)

* Introduce isViewer field

* Update policies

* Make users read-only feature

* Remove not demoting current user validation

* Update tests

* Catch the unhandled promise rejection

* Hide unnecessary ui elements for read-only user

* Update app/scenes/Settings/People.js

Co-authored-by: Tom Moor <tom.moor@gmail.com>

* Remove redundant logic for admin only policies

* Use can logic

* Update snapshot

* Remove lint error

* Update snapshot

* Minor fix

* Update app/menus/UserMenu.js

Co-authored-by: Tom Moor <tom.moor@gmail.com>

* Update server/api/users.js

Co-authored-by: Tom Moor <tom.moor@gmail.com>

* Update app/components/DocumentListItem.js

Co-authored-by: Tom Moor <tom.moor@gmail.com>

* Update app/stores/UsersStore.js

Co-authored-by: Tom Moor <tom.moor@gmail.com>

* Use useCurrentTeam hook in functional component

* Update translation

* Update ternary

* Remove punctuation

* Move the functions to User model

* Update share policy and shareMenu

* Rename makeAdmin to promote

* Create updateCounts function and Rank enum

* Update tests

* Remove enum

* Use async await, remove enum and create computed accessor

* Remove unused variable

* Fix lint issues

* Hide templates

* Create shared/types and use rank type from it

* Delete shared/utils/rank type file

Co-authored-by: Tom Moor <tom.moor@gmail.com>

server/migrations/20210314173941-isViewer.js

@@ -0,0 +1,15 @@
+'use strict';
+
+module.exports = {
+  up: async (queryInterface, Sequelize) => {
+     await queryInterface.addColumn("users", "isViewer", {
+      type: Sequelize.BOOLEAN,
+      defaultValue: false,
+      allowNull: false,
+    });
+  },
+
+  down: async (queryInterface, Sequelize) => {
+    await queryInterface.removeColumn("users", "isViewer");
+  }
+};