Documentation: Project continuity

Documentation: Project continuity

Document project continuity procedures.  This is a plan for a plan for
navigating events that affect the forward progress of the canonical
Linux repository, torvalds/linux.git.

It is a follow-up from Maintainer Summit [1].

Co-developed-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jiri Kosina <jkosina@suse.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lwn.net/Articles/1050179/
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>