Add validation check for projected pod names length

[adejanovski]

What this PR does:
Checks if the projected pod names (for each dc and rack) could overflow the 63 characters limit. Fails the validation if it's the case.

Which issue(s) this PR fixes:
Fixes #1115

Checklist

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

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[codecov]

Codecov Report

Attention: 8 lines in your changes are missing coverage. Please review.

Comparison is base (b39cc4d) 56.83% compared to head (7467eda) 57.02%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1120      +/-   ##
==========================================
+ Coverage   56.83%   57.02%   +0.18%     
==========================================
  Files         100      100              
  Lines       10352    10370      +18     
==========================================
+ Hits         5884     5913      +29     
+ Misses       3950     3939      -11     
  Partials      518      518              

Files	Coverage Δ
...pis/k8ssandra/v1alpha1/k8ssandracluster_webhook.go	69.66% <55.55%> (-3.58%)	⬇️

... and 5 files with indirect coverage changes

[Miles-Garnsey]

Issue: Have we seen this become an issue in practice? I've been reading this article and it indicates that for deployments, truncation of overlength names happens automatically.

But based on this comment I'm not sure if the same applies to statefulsets (particularly because they appear to have other issues with labels), and indeed it may be the case that an STS name over 52 characters will cause issues.

Just trying to figure out what we're doing here.

[sonarqubecloud]

Quality Gate passed

Kudos, no new issues were introduced!

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

See analysis details on SonarCloud