Upgraded gradle build config to use KTS and misc improvements

[kalmanbencze]

Changes:

• using libs.versions.toml file for declaration of library versions
• rewrote build.gradle -> build.gradle.kts with necessary modernization
• rewrote the buildSrc contents/ renamed to build-logic to define convention plugins
• Rewrote the groovy FilamentPlugin.kt in kotlin
• upgraded gradle to gradle-8.14.3
• tested the plugin to convert the resources + samples to verify them
• updated workflows to run on jvm 21

Testing

• regenerated all resources with the rewritten plugin
• tested all samples
• published the libraries to local maven to make sure the publishing works as before

[kalmanbencze]

hey @ThomasGorisse @grassydragon, I got one more change here to modernise the repo a bit. Let me know if I should try and break it into more pieces, although the groovy to kts gradle dsl change would be hard to do one by one

[grassydragon]

Here are my comments after reading through the changes. I'll also try checking out the branch and building the project.

I'd like to hear @ThomasGorisse's opinion on the changes related to publishing.

[grassydragon]

Since the plugin code is now located in build-logic, the manual for adding it to your own project should be updated.

By the way, do you think it's possible to release the plugin as a part of Sceneview? So it can be included as a dependency instead of copying the code.

[kalmanbencze]

hmm I think so, I'll set it up, and if works, I'll update the readme with how to add and run the plugin