algocfg: Add print option to algocfg.

[winder]

Summary

I frequently want to tell people a default configuration according to algocfg, but the only way to use it involves updating/creating a file in the data directory.

This PR adds a new algocfg profile print <profile> subcommand that writes configuration to stdout instead of to a regular file.

Test Plan

Manual testing:

$ algocfg profile print relay
{
	"Archival": true,
	"NetAddress": ":4160",
	"EnableLedgerService": true,
	"EnableBlockService": true
}
$ algocfg profile print conduit
{
	"CatchupParallelBlocks": 64,
	"MaxAcctLookback": 64,
	"EnableFollowMode": true
}
$ algocfg profile print participation
{
}
$ algocfg profile print development
{
	"EnableDeveloperAPI": true,
	"MaxAcctLookback": 256,
	"EnableExperimentalAPI": true,
	"EnableTxnEvalTracer": true,
	"DisableAPIAuth": true
}

[codecov]

Codecov Report

Merging #5824 (6a7af22) into master (c1207a4) will increase coverage by 0.09%.
Report is 6 commits behind head on master.
The diff coverage is 51.42%.

@@            Coverage Diff             @@
##           master    #5824      +/-   ##
==========================================
+ Coverage   55.61%   55.71%   +0.09%     
==========================================
  Files         475      475              
  Lines       66909    66916       +7     
==========================================
+ Hits        37212    37280      +68     
+ Misses      27182    27109      -73     
- Partials     2515     2527      +12     

Files	Coverage Δ
config/localTemplate.go	72.02% <100.00%> (ø)
cmd/algocfg/resetCommand.go	10.52% <0.00%> (ø)
cmd/algocfg/setCommand.go	9.37% <0.00%> (ø)
util/codecs/json.go	68.46% <72.72%> (+56.96%)	⬆️
cmd/algocfg/profileCommand.go	37.33% <10.00%> (-3.58%)	⬇️

... and 11 files with indirect coverage changes

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[jasonpaulos]

Looks good and makes sense. I left a comment about a nit, but I don't consider that a blocker. If that error comes up in the future it can always be addressed then.

[gmalouf]

I think anything we are adding that is reusable across go-algorand should get basic testing, so in this case json.go could use a smoke test.