Add Eclipse P2 repository customizable keystore/truststore configuration

If you are submitting a **bug**, please include the following:

- [X] summary of problem
- [X] Gradle or Maven version
- [X] spotless version
- [X] operating system and version
- [X] copy-paste your full Spotless configuration block(s), and a link to a public git repo that reproduces the problem if possible
- [X] copy-paste the full content of any console errors emitted by `gradlew spotless[Apply/Check] --stacktrace`

If you're just submitting a feature request or question, no need for the above.

* Summary:
Hello, I was running into a situation where I couldn't find any configuration to designate a specific truststore, keystore, and keystore password path for a P2 Mirror host for my eclipse code styles. I'm running on a closed off system during my pipeline builds, which requires a P2 mirror as the normal eclipse one is unreachable. The mirror I can reach requires some SSL handshake with the proper certificate from some custom CA. I wasn't able to figure out a way to point the spotless check to a JKS or P12 I generated with my pipeline's cert or point to a specific cacert store either. Is there proper documentation on this that I potentially missed somewhere?
* Gradle Version: 8.7
* Spotless Version: 6.25.0
* OS: RHEL 9
* Configuration:

```groovy
spotless {
java {
target fileTree('.') {
include '**/*.java'
exclude '**/build/**'
}
eclipse()
.withP2Mirror(['https://download.eclipse.org':'https://mirror_p2_host'])
.configFile("$rootDir/eclipse-code-style.xml")
removeUnusedImports()
formatAnnotations()
indentWithSpace(4)
trimTrailingWhitespace()
endWithNewline()
toggleOffOn()
licenseHeaderFile("$rootDir/license")
}
}
```

* Related Error:

```bash
> Could not determine the dependencies of task ':spotlessCheck'
> Could not create task ':spotlessJavaCheck'
> Could not create task ':spotlessJava'
> java.io.IOException: Failed to load eclipse jdt formatter: java.lang.RuntimeException: javax.net.ssl.SSLHandshakeException: Received fatal alert: certificate_required
```

Commencez par la configuration Gradle `eclipse().withP2Mirror(...)` et suivez la manière dont le formateur Eclipse se connecte au dépôt P2 mis en miroir. Déterminez comment les paramètres personnalisés de keystore, truststore et de mot de passe doivent être exposés ; le travail est terminé lorsque le mirror basé sur un certificat configuré peut charger le formateur sans l’échec de SSL handshake signalé.

Rédigé par le modèle d'indexation à partir du texte de l'issue.