feat: enable i18n (#40937)

Enables the selection of `espanol` for the curriculum build, and sets
`responsive-web-design` as audited for both languages.

Signed-off-by: nhcarrigan <nhcarrigan@gmail.com>

client/i18n/allLangs.js

@@ -3,7 +3,7 @@
  */
 const availableLangs = {
   client: ['english', 'espanol', 'chinese'],
-  curriculum: ['english', 'chinese']
+  curriculum: ['english', 'espanol', 'chinese']
 };
 
 // Each client language needs an entry in the rest of the variables below

utils/is-audited.js

@@ -10,8 +10,8 @@
 // to the arrays below
 
 const auditedCerts = {
-  espanol: [],
-  chinese: []
+  espanol: ['responsive-web-design'],
+  chinese: ['responsive-web-design']
 };
 
 function isAuditedCert(lang, cert) {