Remove Kdenlive adapter for split out

As part of the ongoing outlining process of contrib adapters, this removes the Kdenlive adapter from the core repository.
As discussed with the Kdenlive team (of which @vpinon, the original author, is part), the code has been moved to the KDE GitLab https://invent.kde.org/multimedia/kdenlive-opentimelineio

Related #1378

Signed-off-by: Julius Künzel <[email protected]>

Author: jlskuz

contrib/opentimelineio_contrib/adapters/contrib_adapters.plugin_manifest.json

@@ -48,12 +48,6 @@
             "name": "xges",
             "filepath": "xges.py",
             "suffixes": ["xges"]
-        },
-        {
-            "OTIO_SCHEMA": "Adapter.1",
-            "name": "kdenlive",
-            "filepath": "kdenlive.py",
-            "suffixes": ["kdenlive"]
         }
     ],
     "schemadefs" : [