Doc: Add doc/design-old.txt from clusterlabs wiki

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Signed-off-by: Tim Serong <tserong@suse.com>
Doc: Update status display description in README

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Signed-off-by: Tim Serong <tserong@suse.com>
Doc: Update TODO file

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Signed-off-by: Tim Serong <tserong@suse.com>