Allow overriding cluster configs in quickstarts

[yashmayya]

• The quickstarts currently allow overriding controller / broker / server / minion configs but not cluster configs.
• This patch allows overriding cluster configs in quickstarts which is useful to easily test scenarios involving custom cluster configurations.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.73%. Comparing base (59551e4) to head (d5848d8).
Report is 1625 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #14919      +/-   ##
============================================
+ Coverage     61.75%   63.73%   +1.98%     
- Complexity      207     1470    +1263     
============================================
  Files          2436     2708     +272     
  Lines        133233   151544   +18311     
  Branches      20636    23400    +2764     
============================================
+ Hits          82274    96590   +14316     
- Misses        44911    47702    +2791     
- Partials       6048     7252    +1204     

Flag	Coverage Δ
custom-integration1	100.00% <ø> (+99.99%)	⬆️
integration	100.00% <ø> (+99.99%)	⬆️
integration1	100.00% <ø> (+99.99%)	⬆️
integration2	0.00% <ø> (ø)
java-11	63.71% <ø> (+2.00%)	⬆️
java-21	63.60% <ø> (+1.98%)	⬆️
skip-bytebuffers-false	63.73% <ø> (+1.98%)	⬆️
skip-bytebuffers-true	63.58% <ø> (+35.86%)	⬆️
temurin	63.73% <ø> (+1.98%)	⬆️
unittests	63.73% <ø> (+1.98%)	⬆️
unittests1	56.32% <ø> (+9.43%)	⬆️
unittests2	34.00% <ø> (+6.27%)	⬆️

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