Update to 1.21.10 & improve Gradle build

[LizAinslie]

1.21.10 support!

You can see it live in action on my server's BlueMap

In addition to upgrading the paper-api dependency to support 1.21.10, I've made the following changes:

• chore: update dependencies for bluemap, griefprevention, and commons, use compileOnly instead of long-deprecated provided
• fix: settings.gradle in subprojects is an antipattern, define shadowJar tasks for each

I'll explain each:

Instead of using provided 'some.dependency:coordinate:version, which has been deprecated since Gradle 7.0 and discouraged since Gradle 3.6, the buildscript now uses compileOnly, the new idiomatic api for essentially the same result. I also changed instances of implementation project(":BlueBridgeCore") to use compileOnly as well, since we expect both jars in the plugins folder, avoiding shading the core into each addon.

As for not having a settings.gradle in each subproject, this is necessary to run subproject tasks individually outside of the root directory. Otherwise, Gradle will treat the subproject as a separate project and therefore will not resolve the common allProjects configuration from the root build.gradle. Using allProjects is still generally discouraged in favor of a buildSrc module (which actually should use its own settings.gradle but that is out of the scope of this PR and a time consuming task I did not necessarily want to take on)

Also, consider using a Kotlin buildscript in the future <3
build.gradle.kts while opting to be more verbose in some places, tends to be a lot easier to read for developers hoping to contribute than the old Goovy scripts. It's also recommended by Gradle and the Android team for this reason among others

Anyway, I hope this PR is helpful, cheers! ❤️