migrate to "export default"

also, set no-use-before-define in linter

src/openssl.js

@@ -11,23 +11,6 @@ import shellModule from './shell.js';
 const debug = debugModule('box:openssl');
 const shell = shellModule('openssl');
 
-export {
-    createCsr,
-    generateKey,
-    getModulus,
-    pemToDer,
-    getCertificateDates,
-    getSubjectAndIssuer,
-    generateCertificate,
-    hasExpired,
-    getPublicKey,
-    checkHost,
-    generateDkimKey,
-    generateDhparam,
-    validateCertificate,
-    getSerial,
-    getAuthorityKeyId
-};
 
 async function generateKey(type) {
     debug(`generateKey: generating new key for${type}`);
@@ -241,3 +224,21 @@ async function getAuthorityKeyId(pem) {
     if (!akiMatch) throw new BoxError(BoxError.OPENSSL_ERROR, 'AKI not found');
     return Buffer.from(akiMatch[1].replace(/:/g, ''), 'hex');
 }
+
+export default {
+    createCsr,
+    generateKey,
+    getModulus,
+    pemToDer,
+    getCertificateDates,
+    getSubjectAndIssuer,
+    generateCertificate,
+    hasExpired,
+    getPublicKey,
+    checkHost,
+    generateDkimKey,
+    generateDhparam,
+    validateCertificate,
+    getSerial,
+    getAuthorityKeyId
+};