Add support for FIDO U2F (#3971)

* Add support for U2F

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add vendor library
Add missing translations

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Minor improvements

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add U2F support for Firefox, Chrome (Android) by introducing a custom JS library
Add U2F error handling

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add U2F login page to OAuth

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Move U2F user settings to a separate file

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add unit tests for u2f model
Renamed u2f table name

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Fix problems caused by refactoring

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add U2F documentation

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Remove not needed console.log-s

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add default values to app.ini.sample
Add FIDO U2F to comparison

Signed-off-by: Jonas Franz <info@jonasfranz.software>

public/vendor/librejs.html

@@ -110,6 +110,11 @@
           <td><a href="https://github.com/mozilla/pdf.js/blob/master/LICENSE">Apache-2.0-only</a></td>
           <td><a href="https://github.com/mozilla/pdf.js/archive/v1.4.20.tar.gz">pdf.js-v1.4.20.tar.gz</a></td>
         </tr>
+		<tr>
+		  <td><a href="/vendor/plugins/u2f/">u2f-api</a></td>
+		  <td><a href="https://github.com/go-gitea/u2f-api/blob/master/LICENSE">Expat</a></td>
+		  <td><a href="https://github.com/go-gitea/u2f-api/archive/v1.0.8.zip">u2f-api-1.0.8.zip</a></td>
+		</tr>
         <tr>
           <td><a href="/vendor/assets/font-awesome/fonts/">font-awesome - fonts</a></td>
           <td><a href="http://fontawesome.io/license/">OFL</a></td>