component email message: Mailing list messages cleaning:

For mailing-list messages:
    - convert all text-only messages to XHTML for consistency.
    - detect and flag "noisy" content, i.e. content which are not useful and annoying in
      forum-like view (full-lenght quoted previous messages, mailing-list signature)

rel 464

libervia/backend/plugins/plugin_misc_text_syntaxes.py

@@ -195,16 +195,19 @@ SAFE_CLASSES = {
     "vm",
     "w",
     "write",
+    # "noise" class is used by gateways (in particular email gateway) to mark annoying and
+    # not useful content.
+    "noise"
 }
 STYLES_VALUES_REGEX = (
-    r"^("
+    "^("
     + "|".join(
         [
-            "([a-z-]+)",  # alphabetical names
-            "(#[0-9a-f]+)",  # hex value
-            "(\d+(.\d+)? *(|%|em|ex|px|in|cm|mm|pt|pc))",  # values with units (or not)
-            "rgb\( *((\d+(.\d+)?), *){2}(\d+(.\d+)?) *\)",  # rgb function
-            "rgba\( *((\d+(.\d+)?), *){3}(\d+(.\d+)?) *\)",  # rgba function
+            r"([a-z-]+)",  # alphabetical names
+            r"(#[0-9a-f]+)",  # hex value
+            r"(\d+(.\d+)? *(|%|em|ex|px|in|cm|mm|pt|pc))",  # values with units (or not)
+            r"rgb\( *((\d+(.\d+)?), *){2}(\d+(.\d+)?) *\)",  # rgb function
+            r"rgba\( *((\d+(.\d+)?), *){3}(\d+(.\d+)?) *\)",  # rgba function
         ]
     )
     + ") *(!important)?$"