js: Add jsdoc, update webpack-cli dependency

--
* package.json:
  - the old webpack-cli version depended on two packages
    with vulnerabilities, set to minimum version 3.0.8 to fix this
    (nodesecurity.io/advisories/157, nodesecurity.io/advisories/612)
  - added License identifier

* README: Updated documentation

* jsdoc.conf: Added a configuration file for jsdoc

* some minor documentation changes, indentations

2 files changed, 7 insertions, 6 deletions

diff --git a/lang/js/src/Connection.js b/lang/js/src/Connection.js
index f399b22b..945932e9 100644
--- a/lang/js/src/Connection.js
+++ b/lang/js/src/Connection.js
@@ -40,9 +40,10 @@ export class Connection{
      * Retrieves the information about the backend.
      * @param {Boolean} details (optional) If set to false, the promise will
      *  just return a connection status
-     * @returns {Promise<Object>}
-     *      {String} The property 'gpgme': Version number of gpgme
-     *      {Array<Object>} 'info' Further information about the backends.
+     * @returns {Promise<Object>} result
+     * @returns {String} result.gpgme Version number of gpgme
+     * @returns {Array<Object>} result.info Further information about the
+     * backends.
      *      Example:
      *          "protocol":     "OpenPGP",
      *          "fname":        "/usr/bin/gpg",
diff --git a/lang/js/src/Keyring.js b/lang/js/src/Keyring.js
index 0d7643f0..358757b0 100644
--- a/lang/js/src/Keyring.js
+++ b/lang/js/src/Keyring.js
@@ -110,10 +110,10 @@ export class GPGME_Keyring {
      * contains a secret key.
      * @returns {Promise<GPGME_Key>}
      *
-     * @async
+     *
      * TODO: getHasSecret always returns false at this moment, so this fucntion
      * still does not fully work as intended.
-     *
+     * * @async
      */
     getDefaultKey() {
         let me = this;
@@ -283,7 +283,7 @@ export class GPGME_Keyring {
      * @param {Date} expires (optional) Expiration date. If not set, expiration
      * will be set to 'never'
      *
-     * @returns{Promise<Key>}
+     * @return {Promise<Key>}
      */
     generateKey(userId, algo = 'default', expires){
         if (