feat(operator): Refactor Task, Evaluation handling + adapt span attributes setting

[odubajDT]

Fixes: #376

[codecov-commenter]

Codecov Report

Merging #287 (0a95d74) into main (d2c91d3) will increase coverage by 1.43%.
The diff coverage is 13.66%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #287      +/-   ##
==========================================
+ Coverage   19.45%   20.89%   +1.43%     
==========================================
  Files          13       15       +2     
  Lines        1074     1096      +22     
==========================================
+ Hits          209      229      +20     
- Misses        850      852       +2     
  Partials       15       15              

Impacted Files	Coverage Δ
operator/controllers/common/evaluationhandler.go	0.00% <0.00%> (ø)
operator/controllers/common/taskhandler.go	0.00% <0.00%> (ø)
...or/controllers/keptnworkloadinstance/controller.go	0.00% <0.00%> (ø)
...ptnworkloadinstance/reconcile_prepostdeployment.go	0.00% <0.00%> (ø)
...ptnworkloadinstance/reconcile_prepostevaluation.go	0.00% <0.00%> (ø)
operator/controllers/common/interfaces.go	100.00% <100.00%> (+20.00%)	⬆️
operator/controllers/common/spanhandler.go	67.85% <100.00%> (-3.12%)	⬇️
operator/controllers/keptnapp/controller.go	65.88% <100.00%> (-3.91%)	⬇️

Flag	Coverage Δ
keptn-lifecycle-operator	25.02% <13.66%> (+1.69%)	⬆️
scheduler	4.52% <ø> (ø)

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