Closes #6944 Add LRC hashes when using LRC query string

[Tabrisrp]

Description

Fixes #6944

Add LRC hashes to the HTML when using the wpr_lazyrendercontent query string.

Type of change

• Enhancement (non-breaking change which improves an existing functionality).

Detailed scenario

Details available in #6944

Technical description

Documentation

This PR contains additional internal changes, moving the existing buffer that was previously applied only for image dimensions to the performance hints namespace, updating the name, and splitting the code between the performance hints warmup subscriber, image dimensions subscriber and the LRC subscriber.

This decouples the buffer from the image dimensions namespace to a common one that current and future implementations can use.

Mandatory Checklist

Code validation

• I validated all the Acceptance Criteria. If possible, provide screenshots or videos.
• I triggered all changed lines of code at least once without new errors/warnings/notices.

Code style

• I wrote a self-explanatory code about what it does.
• I protected entry points against unexpected inputs.
• I did not introduce unnecessary complexity.

[Tabrisrp]

This can be reviewed, I'll add the tests for it tomorrow

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ +0.11% (target: -0.10%)	❌ 48.28% (target: 50.00%)

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (b2ae01f)	37937	16553	43.63%
Head commit (7c2274b)	37949 (+12)	16599 (+46)	43.74% (+0.11%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#6955)	29	14	48.28%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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[Tabrisrp]

We're good on coverage here, what remains not covered would not make sense to be tested, so this can go to QA

[Mai-Saad]

Working as expected knowing that we have

• this issue for saas visit OCI & LRC optimizations should not be applied, even if available, on SaaS visits #6964
• this issue for possibly fatal (already at the feature branch) https://wp-media.slack.com/archives/CUT7FLHF1/p1726043509685529?thread_ts=1726037099.524859&cid=CUT7FLHF1
• wpr_lazyrendercontent together with wpr_imagedimensions query string => we inject beacon, URL added to LRC/ATF but not cache table (saas is taking priority as mentioned here Add query string to force LRC hash injection #6944 (comment))
  testrail-report-637.pdf