move clipboard.js to npm/webpack (#10183)

- created lazy-loaded webpack chunk for clipboard.js
- upgraded clipboard.js from 1.5.9 to 2.0.4
- parallelize initialization of all lazy-loaded features

Co-authored-by: Antoine GIRARD <sapk@users.noreply.github.com>

public/vendor/librejs.html

@@ -41,9 +41,9 @@
           <td><a href="https://github.com/go-gitea/gitea/tree/master/web_src/js">*.js</a></td>
         </tr>
         <tr>
-          <td><a href="./plugins/clipboard/clipboard.min.js">clipboard.min.js</a></td>
+          <td><a href="../js/clipboard.js">clipboard.js</a></td>
           <td><a href="http://www.freebsd.org/copyright/freebsd-license.html">Expat</a></td>
-          <td><a href="https://github.com/zenorocha/clipboard.js/archive/v1.5.9.tar.gz">clipboard-1.5.9.tar.gz</a></td>
+          <td><a href="https://github.com/zenorocha/clipboard.js/archive/v2.0.4.tar.gz">clipboard-2.0.4.tar.gz</a></td>
         </tr>
         <tr>
           <td><a href="../js/gitgraph.js">gitgraph.js</a></td>

public/vendor/plugins/clipboard/LICENSE

@@ -1,18 +0,0 @@
-The MIT License
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the 'Software'), to deal in the
-Software without restriction, including without limitation the rights to use,
-copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
-Software, and to permit persons to whom the Software is furnished to do so,
-subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
-PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
-HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.