This largely copies over Spicy's `.clang-format` configuration file. The
one place where we deviate is header include order since Zeek depends on
headers being included in a certain order.
General changes:
* Add -D/--deterministic command line option as
convenience/alternative to -G/--load-seeds (i.e. no file needed, it just
uses zero-initialized random seeds). It also changes Broker data
stores over to using deterministic timing rather than real time.
* Add option to make Reporter abort on runtime scripting errors
