Improves the multikeyfile format by taking a single ship and a list of
life+key pairs, instead of a list of full seeds.
Also decouples these changes from the dawn event, once again putting a
single seed into it. In the multikeyfile case, keys are injected as
%rekey events to jael near the end of the boot sequence.
Haskell-side changes may or may not be incomplete, boot presently fails
at some unknown point with what looks like a noun conversion error.
Allows booting with a keyfile containing multiple keys, as long as one
of them matches current PKI pubkeys for the specified ship.
All relevant keys are loaded into jael and will automatically be put to
use when they match PKI state.
Hoon files may want to import nouns from all files in a given directory.
/~ lets you do so, importing as a (map @ta *) (but with typed values).
Note the description as "directories" here, instead of "path prefix".
The behavior, as implemented, will not include /path/hoon for /~ /path,
instead only including /path/more/hoon and more deeply nested files.
This seems to be, generally, the behavior you want, for example when
importing from /app/myapp/* for /app/myapp/hoon.
Actually using the resulting map requires some manual casting, which is
not ideal. Some code style improvement work remains to be done as well.
