Add remote signer endpoint for GetOrchestratorInfo

[j0sh]

TODO explain

[codecov]

Codecov Report

❌ Patch coverage is 4.00000% with 96 lines in your changes missing coverage. Please review.
✅ Project coverage is 31.46184%. Comparing base (aca2275) to head (f059422).

Files with missing lines	Patch %	Lines
server/remote_signer.go	0.00000%	73 Missing ⚠️
cmd/livepeer/starter/starter.go	16.00000%	21 Missing ⚠️
cmd/livepeer/starter/flags.go	0.00000%	2 Missing ⚠️

Additional details and impacted files

@@                 Coverage Diff                 @@
##              master       #3791         +/-   ##
===================================================
- Coverage   31.52544%   31.46184%   -0.06360%     
===================================================
  Files            159         160          +1     
  Lines          47901       48001        +100     
===================================================
+ Hits           15101       15102          +1     
- Misses         31911       32009         +98     
- Partials         889         890          +1     

Files with missing lines	Coverage Δ
core/livepeernode.go	60.22099% <ø> (ø)
cmd/livepeer/starter/flags.go	0.00000% <0.00000%> (ø)
cmd/livepeer/starter/starter.go	21.90476% <16.00000%> (-0.08388%)	⬇️
server/remote_signer.go	0.00000% <0.00000%> (ø)

... and 2 files with indirect coverage changes

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Files with missing lines	Coverage Δ
core/livepeernode.go	60.22099% <ø> (ø)
cmd/livepeer/starter/flags.go	0.00000% <0.00000%> (ø)
cmd/livepeer/starter/starter.go	21.90476% <16.00000%> (-0.08388%)	⬇️
server/remote_signer.go	0.00000% <0.00000%> (ø)

... and 2 files with indirect coverage changes

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