release process

[meejah]

Hello,

We would like to update the release process so that there isn't a single
private key to sign releases (and thus a potential bottleneck or a
"share access to a private-key, somehow" problem). What we have
converged upon so far is "just have multiple signatures and a document
describing who is expected to produce those". I have made an attempt to
write words to this effect:

   https://github.com/tahoe-lafs/tahoe-lafs/pull/943

Further feedback welcomed (here, or on the above PR). If the examples
instead used the sequoia-pgp tool "sqv" then we could add the
"--signatures 2" option.

-- 
meejah