load balance individual hosts when clusters are to big to distribute

[DaanHoogland]

Description

This PR...

Fixes: #9640

Note 1: this is usefull for smaller installations and/or installations that have a small number of clusters in comparison to the number of hosts.
Note 2: this does not affect or enable realtime rebalancing of direct agents, only attached agents are impacted.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

How did you try to break this feature and the system with this change?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 3.41%. Comparing base (a7a293e) to head (b11258f).
⚠️ Report is 1 commits behind head on main.

❗ There is a different number of reports uploaded between BASE (a7a293e) and HEAD (b11258f). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (a7a293e)	HEAD (b11258f)
unittests	1	0

Additional details and impacted files

@@              Coverage Diff              @@
##               main   #14000       +/-   ##
=============================================
- Coverage     19.73%    3.41%   -16.33%     
=============================================
  Files          6371      487     -5884     
  Lines        575784    41863   -533921     
  Branches      70478     7912    -62566     
=============================================
- Hits         113644     1429   -112215     
+ Misses       449788    40234   -409554     
+ Partials      12352      200    -12152     

Flag	Coverage Δ
uitests	3.41% <ø> (ø)
unittests	?

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