Make it possible to override the license line in the startup banner

This is for Tanzu RabbitMQ, nothing changes for
the open source edition.

(cherry picked from commit b815902)
(cherry picked from commit 4aa1b42)

Author: michaelklishin

deps/rabbit/src/rabbit.erl

@@ -26,6 +26,7 @@
 -export([product_info/0,
          product_name/0,
          product_version/0,
+         product_license_line/0,
          base_product_name/0,
          base_product_version/0,
          motd_file/0,
@@ -919,14 +920,14 @@ start(normal, []) ->
                    [product_name(), product_version(), rabbit_misc:otp_release(),
                     emu_flavor(),
                     BaseName, BaseVersion,
-                    ?COPYRIGHT_MESSAGE, ?INFORMATION_MESSAGE],
+                    ?COPYRIGHT_MESSAGE, product_license_line()],
                    #{domain => ?RMQLOG_DOMAIN_PRELAUNCH});
             _ ->
                 ?LOG_INFO(
                    "~n Starting ~ts ~ts on Erlang ~ts [~ts]~n ~ts~n ~ts",
                    [product_name(), product_version(), rabbit_misc:otp_release(),
                     emu_flavor(),
-                    ?COPYRIGHT_MESSAGE, ?INFORMATION_MESSAGE],
+                    ?COPYRIGHT_MESSAGE, product_license_line()],
                    #{domain => ?RMQLOG_DOMAIN_PRELAUNCH})
         end,
         log_motd(),
@@ -1313,7 +1314,7 @@ print_banner() ->
               "~n  Logs: ~ts" ++ LogFmt ++ "~n"
               "~n  Config file(s): ~ts" ++ CfgFmt ++ "~n"
               "~n  Starting broker...",
-              [Product, Version, ?COPYRIGHT_MESSAGE, ?INFORMATION_MESSAGE] ++
+              [Product, Version, ?COPYRIGHT_MESSAGE, product_license_line()] ++
               [rabbit_misc:otp_release(), emu_flavor(), crypto_version()] ++
               MOTDArgs ++
               LogLocations ++
@@ -1497,6 +1498,10 @@ product_name() ->
         #{product_base_name := BaseName} -> BaseName
     end.
 
+-spec product_license_line() -> string().
+product_license_line() ->
+    application:get_env(rabbit, license_line, ?INFORMATION_MESSAGE).
+
 -spec product_version() -> string().
 
 product_version() ->