feat: implement FindProbedHosts and add LoadRandomHosts to host manager

[gaius-qi]

Description

Related Issue

Motivation and Context

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

[codecov]

Codecov Report

Merging #2519 (da04663) into main (d74ef98) will increase coverage by 0.03%.
The diff coverage is 89.74%.

@@            Coverage Diff             @@
##             main    #2519      +/-   ##
==========================================
+ Coverage   51.91%   51.95%   +0.03%     
==========================================
  Files         154      154              
  Lines       20611    20654      +43     
==========================================
+ Hits        10701    10730      +29     
- Misses       9292     9305      +13     
- Partials      618      619       +1     

Flag	Coverage Δ
Object-compatibility-e2etests	?
e2etests	?
unittests	51.95% <89.74%> (+0.03%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
scheduler/resource/host_manager_mock.go	40.38% <0.00%> (-7.35%)	⬇️
scheduler/resource/host_manager.go	86.44% <76.47%> (-4.04%)	⬇️
pkg/slices/slices.go	100.00% <100.00%> (ø)
scheduler/networktopology/network_topology.go	100.00% <100.00%> (+1.11%)	⬆️
scheduler/service/service_v1.go	80.72% <100.00%> (-0.12%)	⬇️
scheduler/service/service_v2.go	85.61% <100.00%> (-0.09%)	⬇️

... and 2 files with indirect coverage changes