tendermint testnet: Allow for better hostname control

[thanethomson]

This attempts to address issue #3660. It adds two additional flags to the tendermint testnet command:

1. --hostname-suffix - to automatically append a suffix to each and every generated (non-IP) hostname
2. --hostname - a StringArray parameter to manually override all peer hostnames. Using this flag causes tendermint testnet to completely ignore the --hostname-prefix, --hostname-suffix and --starting-ip-address fields.

Example 1 with --hostname-suffix:

> tendermint testnet --v 4 --n 0 --o /tmp/testnet \
    --hostname-prefix mynode \
    --hostname-suffix .xyz.com

> cat /tmp/testnet/node0/config/config.toml | grep persistent_peers
persistent_peers = "42311234da9693ff1affa073f7ef9984a0674582@mynode0.xyz.com:26656,470c1c72deacad25c61673c0b452d5ef99b6053a@mynode1.xyz.com:26656,4a60e1b25e8af75d8688f8c81e93b6c45a8e2991@mynode2.xyz.com:26656,a8d586a3ed4b47b0b04b049445d27113ac031f03@mynode3.xyz.com:26656"

Example 2 with --hostname:

> tendermint testnet --v 4 --n 0 --o /tmp/testnet \
    --hostname alpha.xyz.com \
    --hostname beta.xyz.com \
    --hostname alpha.abcd.com \
    --hostname beta.abcd.com

> cat /tmp/testnet/node0/config/config.toml | grep persistent_peers
persistent_peers = "42311234da9693ff1affa073f7ef9984a0674582@alpha.xyz.com:26656,470c1c72deacad25c61673c0b452d5ef99b6053a@beta.xyz.com:26656,4a60e1b25e8af75d8688f8c81e93b6c45a8e2991@alpha.abcd.com:26656,a8d586a3ed4b47b0b04b049445d27113ac031f03@beta.abcd.com:26656"

• Updated all relevant documentation in docs
• Updated all code comments where relevant
• Wrote tests
• Updated CHANGELOG_PENDING.md

[codecov-io]

Codecov Report

Merging #3661 into develop will increase coverage by 0.15%.
The diff coverage is 22.22%.

@@             Coverage Diff             @@
##           develop    #3661      +/-   ##
===========================================
+ Coverage    63.18%   63.34%   +0.15%     
===========================================
  Files          218      218              
  Lines        18194    18226      +32     
===========================================
+ Hits         11496    11545      +49     
+ Misses        5727     5721       -6     
+ Partials       971      960      -11

Impacted Files	Coverage Δ
cmd/tendermint/commands/testnet.go	18.38% <22.22%> (+1.41%)	⬆️
privval/signer_service_endpoint.go	83.63% <0%> (-1.82%)	⬇️
tools/tm-bench/transacter.go	8.49% <0%> (-0.47%)	⬇️
consensus/state.go	79.97% <0%> (+0.11%)	⬆️
p2p/pex/addrbook.go	68% <0%> (+0.5%)	⬆️
consensus/replay.go	71.02% <0%> (+0.81%)	⬆️
blockchain/pool.go	81.25% <0%> (+0.98%)	⬆️
consensus/reactor.go	72.37% <0%> (+1.77%)	⬆️
p2p/pex/pex_reactor.go	83.97% <0%> (+1.78%)	⬆️
privval/signer_remote.go	82% <0%> (+2%)	⬆️
... and 3 more

[thanethomson]

The latest commit now adds support for the generation of unique monikers for each node configuration generated using the same scheme as for generating peer hostnames (except if --starting-ip-address is used, it will create random hexadecimal strings for monikers). It also adds another command line flag (--random-monikers) which overrides all other configuration to force the tool to generate random hexadecimal strings for monikers.

Previously the command would just use your local hostname, resulting in the same moniker for all nodes. This is not particularly useful when generating configurations for remote nodes, and results in needing to use tools like sed to overwrite the monikers.