Move supported window type masks to matching cpp files

Summary:
SUPPORTED_MANAGED_WINDOW_TYPES_MASK and SUPPORTED_UNMANAGED_WINDOW_TYPES_MASK
are used only in client.cpp and unmanaged.cpp, respectively. So, it doesn't
make sense to keep these two in a header file.

Test Plan: Compiles.

Reviewers: KWin, romangg

Reviewed By: KWin, romangg

Subscribers: romangg, kwin

Tags: KWin

Differential Revision: https://phabricator.kde.org/D24120