In support of dynamic validator list, this changeset:
1. Adds a new `validator_list_expires` field to `server_info` that
indicates when the current validator list will become stale.
2. Adds a new admin only `validator_lists` RPC that returns the
current list of known validators and the most recent published validator
lists.
3. Adds a new admin only `validator_sites` RPC that returns the list of
configured validator publisher sites and when they were most recently
queried.
Manifests of validators newly added to a published validator list are
not reliably propagated to network nodes.
This solves the problem by allowing a published validator list to
include the manifest.
RIPD-1559
* Use fixed size UNL if the total listed validators are below
threshold.
* Set quorum to provide Byzantine fault tolerance until a
threshold of total validators is exceeded, at which time
quorum is 80%.
* Ensure that a quorum of 0 cannot be configured.
Instead of specifying a static list of trusted validators in the config
or validators file, the configuration can now include trusted validator
list publisher keys.
The trusted validator list and quorum are now reset each consensus
round using the latest validator lists and the list of recent
validations seen. The minimum validation quorum is now only
configurable via the command line.
Replace Journal public data members with member function accessors
in order to make Journal lighter weight. The change makes a
Journal cheaper to pass by value.
Also add missing stream checks (e.g., calls to JLOG) to avoid
text processing that ultimately will not be stored in the log.
The RippleAddress class was used to represent a number of fundamentally
different types: account public keys, account secret keys, node public
keys, node secret keys, seeds and generators.
The class is replaced by the following types:
* PublicKey for account and node public keys
* SecretKey for account and node private keys
* Generator for generating secp256k1 accounts
* Seed for account, node and generator seeds
The new code removes the ability to specify domain names
in the [validators] configuration block, and no longer
supports the [validators_site] option.
More details on the supported configurations are available
under doc/rippled-example.cfg.
