feat: Move to passport for authentication (#1934)

- Added `accountProvisioner`
- Move authentication to use passport strategies
- Make authentication more pluggable
- Change language of services -> providers

closes #1120

server/migrations/20210310051804-passport.js

@@ -0,0 +1,19 @@
+'use strict';
+
+module.exports = {
+  up: async (queryInterface, Sequelize) => {
+    await queryInterface.removeColumn("users", "slackData");
+    await queryInterface.removeColumn("teams", "slackData");
+  },
+
+  down: async (queryInterface, Sequelize) => {
+    await queryInterface.addColumn("teams", "slackData", {
+      type: 'JSONB',
+      allowNull: true,
+    });
+    await queryInterface.addColumn("users", "slackData", {
+      type: 'JSONB',
+      allowNull: true,
+    });
+  }
+};