[FIX] *: add explicit license to all manifest

The license is missing in most enterprise manifest so
the decision was taken to make it explicit in all cases.
When not defined, a warning will be triggered starting from
14.0 when falling back on the default LGPL-3.

closes odoo/design-themes#48

Related: odoo/odoo#74245
Related: odoo/enterprise#19862
Signed-off-by: Xavier Dollé (xdo) <xdo@odoo.com>

theme_common/__manifest__.py

@@ -12,4 +12,5 @@
         'views/old_snippets/s_three_columns_circle.xml',
         ],
     'application': False,
+    'license': 'LGPL-3',
 }