[ADD] base: explicit rtlcss configuration

Changes in default can be bothersome, embed a full baseline
configuration for reliability.

closes odoo/odoo#27926

Signed-off-by: Pierre Masereel <pim@odoo.com>

odoo/addons/base/data/rtlcss.json

+{
+    "options": {
+        "autoRename": false,
+        "autoRenameStrict": false,
+        "blacklist": {
+            "rtlcss": {
+                "config": true,
+                "options": true
+            }
+        },
+        "clean": true,
+        "greedy": false,
+        "processUrls": false,
+        "stringMap": [],
+        "useCalc": false,
+        "aliases": {},
+        "processEnv": false
+    },
+    "plugins": [],
+    "map": false
+}

odoo/addons/base/models/assetsbundle.py

@@ -573,8 +573,8 @@ class AssetsBundle(object):
                 rtlcss = misc.find_in_path('rtlcss.cmd')
             except IOError:
                 rtlcss = 'rtlcss'
-        cmd = [rtlcss, '-']
 
+        cmd = [rtlcss, '-c', get_resource_path("base", "data/rtlcss.json"), '-']
 
         try:
             rtlcss = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)