MB-11341: Add support for running Clang static analyser

Adds a `make analyze` convenience rule to run Clang's static analyzer
over the whole codebase. See README.markdown for more details and full
instructions.

Change-Id: I5a2484729335e8f38417f17236a8a3b78c16d872
Reviewed-on: http://review.couchbase.org/37955
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>