tools: nodecfg without dns

[brianolson]

Summary

It is possible to run a test cluster without dns, relying on phonebook.json instead. This makes test clusters slightly faster to set up and more reliable for not relying on the dns service.

Test Plan

This has been demonstrated manually in a test cluster.

[codecov]

Codecov Report

Merging #4967 (ca10b05) into master (a35f4b8) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #4967   +/-   ##
=======================================
  Coverage   53.67%   53.67%           
=======================================
  Files         432      432           
  Lines       54077    54077           
=======================================
+ Hits        29025    29027    +2     
+ Misses      22806    22801    -5     
- Partials     2246     2249    +3     

Impacted Files	Coverage Δ
ledger/roundlru.go	90.56% <0.00%> (-5.67%)	⬇️
crypto/merkletrie/trie.go	66.42% <0.00%> (-2.19%)	⬇️
crypto/merkletrie/node.go	91.62% <0.00%> (-1.87%)	⬇️
ledger/acctupdates.go	68.99% <0.00%> (-0.25%)	⬇️
catchup/service.go	69.80% <0.00%> (ø)
ledger/blockqueue.go	88.50% <0.00%> (+2.87%)	⬆️
ledger/tracker.go	78.90% <0.00%> (+3.79%)	⬆️

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