Remove the WLM protocol
Summary:
Microsoft discontinued the Windows Live Messenger service in 2013, so
this protocol is effectively dead.
As a result:
- remove the code of the protocol itself
- remove all the supporting cmake stuff
- remove one notification specific to it
- slightly update the documentation to not mention WLM anymore
This way, developers/downstreams will not try to accidentally build/ship
this anymore.
Test Plan: Builds fine
Reviewers: kde-i18n-doc, pali, aacid
Reviewed By: aacid
Subscribers: kde-i18n-doc, Kopete
Tags: Kopete
Differential Revision: https://phabricator.kde.org/D12530