feat: add basic sticky-sessions support

[tao12345666333]

What this PR does / why we need it:

Which issue this PR fixes:

part of #7418

Special notes for your reviewer:

PR Readiness Checklist:

Complete these before marking the PR as ready to review:

• the CHANGELOG.md release notes have been updated to reflect any significant (and particularly user-facing) changes introduced by this PR

[codecov]

Codecov Report

Attention: Patch coverage is 95.91837% with 2 lines in your changes missing coverage. Please review.

Project coverage is 77.3%. Comparing base (6ecb0c5) to head (4017786).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ternal/dataplane/translator/translate_upstreams.go	94.7%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #7466     +/-   ##
=======================================
- Coverage   77.3%   77.3%   -0.1%     
=======================================
  Files        220     220             
  Lines      25372   25407     +35     
=======================================
+ Hits       19623   19643     +20     
- Misses      4747    4767     +20     
+ Partials    1002     997      -5     

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[tao12345666333]

This section is currently a placeholder, I need to make modifications based on the specific implementation of the Gateway.

[pmalek]

Does this still require more work or can we move forward with currently set value here?

[tao12345666333]

@pmalek In the current gateway implementation, the algorithm name is set to "sticky-sessions"

xref： https://github.com/Kong/kong-ee/pull/12524

[pmalek]

Ok, can you be more specific what does that mean for us? What work is still required? What changes still need (if any) to be done?

[tao12345666333]

This means we need to change the manifest according to the implementation in the gateway. I think the other parts do not need to be adjusted.

[pmalek]

according to the implementation in the gateway

That means specifically what exactly? We need to change the hashOn settings? We need to change the session-script ConfigMap? I think that this needs to be written down somewhere.

I've reopened #7418 to cover this work (as I understand there is still something to be done for this feature). LMYK if that works for you.

[tao12345666333]

I guess I can submit a PR when I'm available (in a few hours)

[justindavies]

Was this update made ? OR is it simply I need to update the alorithm in the manofest to be sticky-sessions ?

[pmalek]

The updated manifest can be found in #7495

[sandromodarelli]

lgtm

[pmalek]

I'm sorry it's just now that I realized this but I believe we should remove this test:

• This test shouldn't really be placed in this directory.

  This is not an integration test, it doesn't use the cluster in any way of nor it interacts with it using any of the clients that we typically use in integration tests.

• Secondly and more importantly, this doesn't really test anything. Note that the only interaction that this test has with KIC's packages is util.Endpoint which it creates in the test body itself, not through any of the functions or types added in this PR.

Having said that I believe we should remove this test and ideally add a proper one that verifies the added functionality.