*: Fix icons not present in the generated .deb

Closes: #2352.

Perform a recursive glob with '**' when performing search files to installed
from static folder so that icons files are found and installed as extra package
data.

Tests:

- Build a .deb package and confirm that none of the icons files have been
installed into /usr/lib/python3/dist-packages/plinth directory. With the fix,
rebuild the package and confirm that .png and .svg files are present at least
some plinth/modules/*/static/icons/* path.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: James Valleroy <jvalleroy@mailbox.org>

setup.py

@@ -319,7 +319,7 @@ setuptools.setup(
         'tomli',
     ],
     package_data={
-        '': ['templates/*', 'static/*', 'locale/*/LC_MESSAGES/*.mo']
+        '': ['templates/*', 'static/**', 'locale/*/LC_MESSAGES/*.mo']
     },
     exclude_package_data={'': ['*/data/*']},
     data_files=_gather_data_files() +