pidgin/pidgin

Modernizing PurpleChatConversation.

2021-04-05, Gary Kramlich
73407e00ec5d
Modernizing PurpleChatConversation.

I wasn't able to do everything as PurpleConversation still isn't declared with
G_DECLARE_DERIVABLE_TYPE.

Testing Done:
Compiled ran locally with both xmpp mucs and irc channels.

Reviewed at https://reviews.imfreedom.org/r/583/
libpurple/data/purple-url-handler.desktop.in
libpurple/protocols/null/nullprpl.c
pidgin/data/im.pidgin.Pidgin.desktop.in
sub/libpurple/data/purple-url-handler.desktop.in
sub/libpurple/protocols/null/nullprpl.c
sub/pidgin/data/im.pidgin.Pidgin.desktop.in