Support attributes in stateful session cookies (#40084)

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Commit Message: support attributes in stateful session cookies
Additional Description: Today setting attributes in stateful session
cookies is not supported natively. A follow up filter modifies the
cookie to add attributes, e.g. a Lua script. This improves UX for this
usecase.
Risk Level: Minor
Testing: Unit testing
Docs Changes: TBD
Release Notes: TBD
Platform Specific Features: N/A
Fixes #36846

Signed-off-by: Rudrakh Panigrahi <[email protected]>

Mirrored from https://github.com/envoyproxy/envoy @ 39339150a76959fac0ef47b85441f38fe27d061c

Author: update-envoy[bot]

envoy/type/http/v3/cookie.proto

@@ -28,4 +28,20 @@ message Cookie {
   // Path of cookie. This will be used to set the path of a new cookie when it is generated.
   // If no path is specified here, no path will be set for the cookie.
   string path = 3;
+
+  // Additional attributes for the cookie. They will be used when generating a new cookie.
+  repeated CookieAttribute attributes = 4;
+}
+
+// CookieAttribute defines an API for adding additional attributes for a HTTP cookie.
+message CookieAttribute {
+  // The name of the cookie attribute.
+  string name = 1
+      [(validate.rules).string =
+           {min_len: 1 max_bytes: 16384 well_known_regex: HTTP_HEADER_NAME strict: false}];
+
+  // The optional value of the cookie attribute.
+  string value = 2 [
+    (validate.rules).string = {max_bytes: 16384 well_known_regex: HTTP_HEADER_VALUE strict: false}
+  ];
 }