pidgin/pidgin

Convert credentials page to use HdyPreferencesGroup and a list box.

2021-05-12, Elliott Sales de Andrade
68c7ef6c5320
Convert credentials page to use HdyPreferencesGroup and a list box.

* Convert credentials page to use `HdyPreferencesGroup` and a list box.
* Add widget for displaying a credential provider in a list box.
* Convert `PidginCredentialsPage` into `HdyPreferencesPage`.

Testing Done:
Opened Preferences, switch to Credentials page, and see/toggle selected provider.

Reviewed at https://reviews.imfreedom.org/r/644/
[Desktop Entry]
Name=Pidgin
GenericName=Internet Messenger
Comment=Chat over IM. Supports Jabber/XMPP, and more
Exec=purple3-url-handler %u
TryExec=purple3-url-handler
Icon=pidgin
StartupNotify=false
Terminal=false
NoDisplay=true
Type=Application
Categories=Network;InstantMessaging;RemoteAccess;ConsoleOnly;
MimeType=x-scheme-handler/gg;x-scheme-handler/irc;x-scheme-handler/sip;x-scheme-handler/xmpp;
@USES_MM_CHAT_SECTION@