Create Medusa CronJob in operator namespace

[emerkle826]

What this PR does:
Creates the Medusa purge CronJob in the operator namespace (instead of the K8ssandra Cluster namespace)

Which issue(s) this PR fixes:
Fixes #1226

Checklist

• Changes manually tested
• Automated Tests added/updated
• Documentation added/updated
• CHANGELOG.md updated (not required for documentation PRs)
• CLA Signed: DataStax CLA

[codecov]

Codecov Report

Attention: Patch coverage is 87.50000% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 57.32%. Comparing base (6ad0ed0) to head (c927ccd).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1227      +/-   ##
==========================================
+ Coverage   57.30%   57.32%   +0.02%     
==========================================
  Files         103      103              
  Lines       10794    10801       +7     
==========================================
+ Hits         6185     6192       +7     
- Misses       4069     4070       +1     
+ Partials      540      539       -1     

Files	Coverage Δ
controllers/k8ssandra/medusa_reconciler.go	64.65% <87.50%> (+0.70%)	⬆️

... and 2 files with indirect coverage changes

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud