chore!: remove Keptn scheduler

[odubajDT]

Changes

• removes Keptn scheduler code
• removes Keptn scheduler from pipelines
• removes Keptn scheduler from helm charts
• adapts helm chart to use only scheduling gates
• adapts lifecycle operator to use only scheduling gates
• regenerates helm docs
• regenerates helm test results

Follow-up

• adapt docs (include 1.27 as latest supported version)
• adapt examples
• verify Keptn works

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.70%. Comparing base (5be9abe) to head (a84d5e6).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3821      +/-   ##
==========================================
+ Coverage   76.64%   77.70%   +1.05%     
==========================================
  Files         224      219       -5     
  Lines       11883    11575     -308     
==========================================
- Hits         9108     8994     -114     
+ Misses       2405     2216     -189     
+ Partials      370      365       -5     

Files with missing lines	Coverage Δ
...rator/webhooks/pod_mutator/pod_mutating_webhook.go	95.71% <100.00%> (-0.34%)	⬇️

... and 2 files with indirect coverage changes

Flag	Coverage Δ
certificate-operator	47.44% <ø> (ø)
component-tests	57.08% <ø> (-22.06%)	⬇️
lifecycle-operator	79.68% <100.00%> (-0.02%)	⬇️
metrics-operator	75.91% <ø> (ø)
scheduler	?

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud