More metrics

[pm47]

This adds metrics on bitcoin rpc calls and on scodec.

[codecov-io]

Codecov Report

Merging #1196 into master will decrease coverage by 8.61%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1196      +/-   ##
==========================================
- Coverage   84.06%   75.45%   -8.62%     
==========================================
  Files         104      135      +31     
  Lines        7928     9076    +1148     
  Branches      345      352       +7     
==========================================
+ Hits         6665     6848     +183     
- Misses       1263     2228     +965

Impacted Files	Coverage Δ
.../fr/acinq/eclair/wire/LightningMessageCodecs.scala	100% <100%> (ø)	⬆️
...in/bitcoind/rpc/BatchingBitcoinJsonRPCClient.scala	100% <100%> (ø)	⬆️
...ore/src/main/scala/fr/acinq/eclair/PimpKamon.scala	100% <100%> (+100%)	⬆️
...chain/bitcoind/rpc/BasicBitcoinJsonRPCClient.scala	100% <100%> (ø)	⬆️
.../main/scala/fr/acinq/eclair/io/Authenticator.scala	92.59% <100%> (ø)	⬆️
...-core/src/main/scala/fr/acinq/eclair/io/Peer.scala	75.44% <100%> (-0.3%)	⬇️
.../acinq/eclair/blockchain/bitcoind/ZmqWatcher.scala	96.22% <100%> (+0.07%)	⬆️
...in/scala/fr/acinq/eclair/wire/FailureMessage.scala	79.1% <100%> (ø)	⬆️
.../fr/acinq/eclair/gui/stages/OpenChannelStage.scala	0% <0%> (ø)
... and 32 more