Move dependency constraints to root build script

[RenFraser]

This removes the platform project and helps to simplify the build logic around constraining dependency versions by moving it out of the gradle directory and into the root directory. It looks like we've moved the plugins into buildSrc in a similar way, so this follows suit. Hopefully, this will make it easier to maintain.

It also removes duplicate constraint entries and a an error when the language server parses its own codebase and finds the platform project (that's now been removed).

[themkat]

Less files = easier to read and understand in my view 🙂 Let's give other people a few days to weigh in with their opinion.

[fwcd]

I think using subprojects and imperative plugin applications is the legacy way of doing this andgenerally discouraged in favor of version catalogs and build platforms

[RenFraser]

In my notes, I've got a version catalog as the alternative to a BOM for modern Gradle. I went with the BOM not too long ago because of the syntax but reading the docs here hat you've linked), I like how we can define libraries in a settings file, such as:

dependencyResolutionManagement {
    versionCatalogs {
        create("libs") {
            version("groovy", "3.0.5")
            version("checkstyle", "8.37")
            library("groovy-core", "org.codehaus.groovy", "groovy").versionRef("groovy")
            library("groovy-json", "org.codehaus.groovy", "groovy-json").versionRef("groovy")
            library("groovy-nio", "org.codehaus.groovy", "groovy-nio").versionRef("groovy")
            library("commons-lang3", "org.apache.commons", "commons-lang3").version {
                strictly("[3.8, 4.0[")
                prefer("3.9")
            }
        }
    }
}

And then use them elsewhere by:

dependencies {
    implementation(libs.groovy.core)
    implementation(libs.groovy.json)
    implementation(libs.groovy.nio)
}

To me, the catalog written this way is clearer than both the TOML syntax and the BOM that's already present. What do you think @themkat and @fwcd ? Perhaps this would be a better way forward.

[RenFraser]

I'm going to cancel this PR to focus on more pressing issues with the language server.