deps: i18next 10 -> 23, react-i18next 7 -> 14

Modernizes the whole i18n stack:
- 48 translate([], {wait:true}) / translate() HOCs -> withTranslation()
- react.wait:true -> react.useSuspense:false
- whitelist -> supportedLngs; added compatibilityJSON: 'v3' so our
  natural-language keys + v3 _plural layout keep working (custom
  separators ss/eth/dj preserved)
- backends: xhr -> i18next-http-backend (client), sync-fs ->
  i18next-fs-backend (server); dropped i18next-localstorage-cache
  (was enabled:false); languagedetector 2 -> 8
- ReSendEmail: <Interpolate> (removed in v10) -> <Trans values={{email}}/>,
  dropped the removed bare t export
- saveMissing handler signature (lngs, ns, key, fallbackValue)

Silences the per-component Translate/I18n legacy-context warnings.
Browser-verified es/en switch and <Trans> interpolation on /fires;
REST smoke byte-identical.

imports/ui/components/Feedback/Feedback.js

@@ -5,7 +5,7 @@
 import React, { Component } from 'react';
 import PropTypes from 'prop-types';
 import { Meteor } from 'meteor/meteor';
-import { translate } from 'react-i18next';
+import { withTranslation } from 'react-i18next';
 import { FormGroup, Button, FormControl } from 'react-bootstrap';
 import { Bert } from 'meteor/themeteorchef:bert';
 import { withTracker } from 'meteor/react-meteor-data';
@@ -134,7 +134,7 @@ Feedback.propTypes = {
   isHome: PropTypes.bool.isRequired
 };
 
-export default translate()(withTracker(props => ({
+export default withTranslation()(withTracker(props => ({
   emailAddress: props.emailAddress,
   emailVerified: props.emailVerified,
   isHome: isHome()