feat: Add new -rsh/--remoteServiceHosts flag and corresponding env override

[lenny-goodell]

closes #593

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PR Checklist

Please check if your PR fulfills the following requirements:

• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• I am not introducing a new dependency (add notes below if you are)
• I have added unit tests for the new feature or bug fix (if not, why?)
• I have fully tested (add details below) this the new feature or bug fix (if not, why?)
• I have opened a PR for the related docs change (if not, why?)
  feat: Document new -rsh/--remoteServiceHosts flag and env override edgex-docs#1213

Testing Instructions

Run non-secure edgex stack
Build App Template (in App SDK) with this branch (replace in go.mods)
run ./app-new-service -cp -r -rsh=172.26.113.174,172.26.113.174,0.0.0.0
verify the service bootstraps successfully
verify the log contains the following:

• Setting config Provider host to 172.26.113.174
• Using Configuration provider (consul) from: http://172.26.113.174:8500
• Using Registry (consul) from http://172.26.113.174:8500
• Connected to redis Message Bus @ redis://172.26.113.174:6379
• Using REST for 'core-metadata' clients @ http://172.26.113.174:59881
• Using REST for 'core-data' clients @ http://172.26.113.174:59880
• Using REST for 'support-notifications' clients @ http://172.26.113.174:59860
• Starting HTTP Web Server on address 0.0.0.0:59740

run REMOTE_SERVICE_HOSTS=172.26.113.174,172.26.113.174,0.0.0.0 ./app-new-service -cp -r
verify the service bootstraps successfully
verify the log contains the same above contents:

New Dependency Instructions (If applicable)

[codecov-commenter]

Codecov Report

Merging #596 (c43454d) into main (f8054bb) will decrease coverage by 0.16%.
The diff coverage is 46.05%.

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@@            Coverage Diff             @@
##             main     #596      +/-   ##
==========================================
- Coverage   58.97%   58.81%   -0.16%     
==========================================
  Files          31       31              
  Lines        2469     2523      +54     
==========================================
+ Hits         1456     1484      +28     
- Misses        917      942      +25     
- Partials       96       97       +1     

Files Changed	Coverage Δ
bootstrap/flags/flags.go	56.32% <15.38%> (-3.68%)	⬇️
bootstrap/config/provider.go	75.00% <25.00%> (-10.72%)	⬇️
bootstrap/config/config.go	32.79% <52.94%> (+1.17%)	⬆️
bootstrap/environment/variables.go	89.51% <100.00%> (+0.28%)	⬆️
bootstrap/handlers/clients.go	95.78% <100.00%> (ø)

[lenny-goodell]

@cloudxxx8 please review and let me know if you agree with the flag name. Doc PR is here: edgexfoundry/edgex-docs#1213

Address comments