jsxc: Fix issue with serving static files

During the re-organization of data files into individual apps, a regression for
JSXC preventing the symbolic links in the source code from being copied to
destination folder during 'setup.py install'. Fix this by removing symbolic
links and serving the file using CherryPy mappings with the help of StaticFiles
component.

Closes: #1180.

Tests performed:

- Access the following URLs successfully:
  https://localhost:4430/plinth/static/jsxc/img/menu_black.svg
  https://localhost:4430/plinth/static/jsxc/libjs-jsxc/jsxc.css
  https://localhost:4430/plinth/static/jsxc/libjs-jsxc/sound/Ping1.mp3
  https://localhost:4430/plinth/static/jsxc/libjs-jsxc/lib/otr/lib/dsa-webworker.js

- Login to JSXC, see the roster properly on the right side.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Veiko Aasa <veiko17@disroot.org>

plinth/modules/jsxc/__init__.py

@@ -11,6 +11,7 @@ from django.utils.translation import ugettext_lazy as _
 from plinth import app as app_module
 from plinth import frontpage, menu
 from plinth.modules.firewall.components import Firewall
+from plinth.web_server import StaticFiles
 
 from .manifest import backup, clients  # noqa, pylint: disable=unused-import
 
@@ -58,6 +59,16 @@ class JSXCApp(app_module.App):
                             ports=['http', 'https'], is_external=True)
         self.add(firewall)
 
+        directory_map = {
+            '/static/jsxc/img': '/usr/share/libjs-jsxc/img/',
+            '/static/jsxc/libjs-jsxc/lib': '/usr/share/javascript/jsxc/lib/',
+            '/static/jsxc/libjs-jsxc/sound': '/usr/share/libjs-jsxc/sound/',
+            '/static/jsxc/libjs-jsxc/': '/usr/share/libjs-jsxc/css/',
+        }
+        static_files = StaticFiles('static-files-jsxc',
+                                   directory_map=directory_map)
+        self.add(static_files)
+
 
 def init():
     """Initialize the JSXC module"""

plinth/modules/jsxc/static/img

@@ -1 +0,0 @@
-/usr/share/libjs-jsxc/img/

plinth/modules/jsxc/static/libjs-jsxc/jsxc.css

@@ -1 +0,0 @@
-/usr/share/libjs-jsxc/css/jsxc.css

plinth/modules/jsxc/static/libjs-jsxc/lib

@@ -1 +0,0 @@
-/usr/share/javascript/jsxc/lib

plinth/modules/jsxc/static/libjs-jsxc/sound

@@ -1 +0,0 @@
-/usr/share/libjs-jsxc/sound/