Migrate version.gradle script plugin to Kotlin convention plugin

[bric3]

What does it do

Replaces the Groovy version.gradle script plugin with a convention plugin dd-trace-java.version-file.

There's 20 consumers they are now declarign it in plugins {} block (or apply plugin: where plugins {} is not available).

Adds tests for this plug-in.

Motivation

1. Project.exec {} is removed in Gradle 9. It is also incompatible with the configuration cache.
2. version.gradle is a Groovy script plugin, migrating to convention plugin is the way to go.

Additional Notes

Sub-PR of #10402, #11272.

[AlexeyKuznetsov-DD]

One more step in removing Groovy! Nice!

[pr-commenter]

Debugger benchmarks

Parameters

	Baseline	Candidate
baseline_or_candidate	baseline	candidate
ci_job_date	1778519214	1778519560
end_time	2026-05-11T17:08:20	2026-05-11T17:14:06
git_branch	master	bdu/gradle9-write-version-convention-plugin
git_commit_sha	a7c5921	72991c0
start_time	2026-05-11T17:06:55	2026-05-11T17:12:41

See matching parameters

	Baseline	Candidate
ci_job_id	1673135604	1673135604
ci_pipeline_id	112530234	112530234
cpu_model	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz	Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz
git_commit_date	1778518662	1778518662

Summary

Found 0 performance improvements and 0 performance regressions! Performance is the same for 9 metrics, 6 unstable metrics.

See unchanged results

scenario	Δ mean agg_http_req_duration_min	Δ mean agg_http_req_duration_p50	Δ mean agg_http_req_duration_p75	Δ mean agg_http_req_duration_p99	Δ mean throughput
scenario:noprobe	unstable [-22.377µs; +29.707µs] or [-7.659%; +10.168%]	unstable [-34.043µs; +43.620µs] or [-10.149%; +13.004%]	unstable [-45.099µs; +57.785µs] or [-12.823%; +16.429%]	unstable [-128.029µs; +100.192µs] or [-10.219%; +7.997%]	same
scenario:basic	same	same	same	unstable [-209.386µs; +31.066µs] or [-16.969%; +2.518%]	unstable [-218.673op/s; +96.722op/s] or [-8.747%; +3.869%]
scenario:loop	same	same	same	same	same

Request duration reports for reports

gantt
    title reports - request duration [CI 0.99] : candidate=None, baseline=None
    dateFormat X
    axisFormat %s
section baseline
noprobe (335.432 µs) : 304, 367
.   : milestone, 335,
basic (296.257 µs) : 290, 303
.   : milestone, 296,
loop (8.972 ms) : 8967, 8977
.   : milestone, 8972,
section candidate
noprobe (340.22 µs) : 298, 382
.   : milestone, 340,
basic (297.494 µs) : 290, 305
.   : milestone, 297,
loop (8.972 ms) : 8967, 8977
.   : milestone, 8972,

Loading

• baseline results

Scenario	Request median duration [CI 0.99]
noprobe	335.432 µs [304.188 µs, 366.676 µs]
basic	296.257 µs [289.936 µs, 302.578 µs]
loop	8.972 ms [8.967 ms, 8.977 ms]

• candidate results

Scenario	Request median duration [CI 0.99]
noprobe	340.22 µs [298.398 µs, 382.042 µs]
basic	297.494 µs [290.201 µs, 304.787 µs]
loop	8.972 ms [8.967 ms, 8.977 ms]

[sarahchen6]

🎉