Make password hashing algorithm/cost configurable for the
stored passwords of users for the realms that this applies
(native, reserved). Replaces predefined choice of bcrypt with
cost factor 10.
This also introduces PBKDF2 with configurable cost
(number of iterations) as an algorithm option for password hashing
both for storing passwords and for the user cache.
Password hash validation algorithm selection takes into
consideration the stored hash prefix and only a specific number
of algorithnm and cost factor options for brypt and pbkdf2 are
whitelisted and can be selected in the relevant setting.
This commit upgrades us to Netty 4.1.25. This upgrade is more
challenging than past upgrades, all because of a new object cleaner
thread that they have added. This thread requires an additional security
permission (set context class loader, needed to avoid leaks in certain
scenarios). Additionally, there is not a clean way to shutdown this
thread which means that the thread can fail thread leak control during
tests. As such, we have to filter this thread from thread leak control.
This commit makes x-pack a module and adds it to the default
distrubtion. It also creates distributions for zip, tar, deb and rpm
which contain only oss code.