Remove Piwik support (#8835)

* Remove all mentions of Piwik

* Kill off all consumer of the old Piwik Analytics module

* Simplify ModalManager interface

* i18n

* Attempt to fix old e2e tests

* Remove unused component

* Iterate PR

src/components/views/dialogs/DeactivateAccountDialog.tsx

@@ -19,7 +19,6 @@ import React from 'react';
 import { AuthType, IAuthData } from 'matrix-js-sdk/src/interactive-auth';
 import { logger } from "matrix-js-sdk/src/logger";
 
-import Analytics from '../../../Analytics';
 import { MatrixClientPeg } from '../../../MatrixClientPeg';
 import { _t } from '../../../languageHandler';
 import InteractiveAuth, { ERROR_USER_CANCELLED, InteractiveAuthCallback } from "../../structures/InteractiveAuth";
@@ -122,7 +121,6 @@ export default class DeactivateAccountDialog extends React.Component<IProps, ISt
         // this isn't done.
         MatrixClientPeg.get().deactivateAccount(auth, this.state.shouldErase).then(r => {
             // Deactivation worked - logout & close this dialog
-            Analytics.trackEvent('Account', 'Deactivate Account');
             defaultDispatcher.fire(Action.TriggerLogout);
             this.props.onFinished(true);
         }).catch(e => {