Change jsonrpc4j version from 1.5.3 to 1.6.0.bisq.1, forked to the Bisq
repo from the recent 1.6.0 release. The forked version changes the class
'com.googlecode.jsonrpc4j.HttpException' to be public, instead of (prob.
mistakenly) package private, so we can avoid using reflection to catch
it and re-throw as a 'bisq.network.http.HttpException'. Remove the now
unused constructors from the latter.
As part of this, upgrade Jackson to the latest stable (2.12.1) release,
since jsonrpc4j now depends on a newer version than the previous 2.8.10.
Migrate RpcService over to the new block notification daemon and RPC
client based on jsonrpc4j. Drop in own DTO classes in place of the ones
defined by btcd-cli4j and rename requestBtcBlock & addNewBtcBlockHandler
to requestDtoBlock & addNewDtoBlockHandler respectively.
Also remove now redundant filtering from the logback config and update
grade-witness.
Create a new 'BitcoindClient' interface and a corresponding builder, to
replace the old 'com.neemre.btcdcli4j.core.client.BtcdClientImpl' class
from the btcdcli4j library. This is instantiated by jsonrpc4j using a
dynamic proxy. It provides only a cut down version of the bitcoind RPC
API, exposing the methods 'getblock', 'getblockcount' & 'getblockhash',
as they are the only ones currently being used by RpcService.
Add corresponding Jackson-annotated DTO classes to model the JSON
structures returned by bitcoind, very similar to the classes provided by
btcdcli4j. Note that we use Double instead of BigDecimal to represent
fractional fields (difficulties + coin amounts in BTC), as they have
more consistent Jackson (de)serialisation and appear to be able to
faithfully round-trip numeric fields produced by bitcoind. Also note
that doubles can faithfully represent any valid decimal BTC amount (that
is, with 8 d.p. of precision) up to 21 million.
For now, keep the old BtcdClientImpl instance used by RpcService in
place, as the btcdcli4j block notification daemon is dependent upon it
and would also need to be replaced.
Also add unit tests for BitcoindClient which test against sample regtest
responses, using a mock HttpURLConnection.
