🧹 Clean up the gradle build scripts a little

Changes:
- Move all dependency versions to a shared file
- Order the projects in settings.gradle

build.gradle

@@ -17,6 +17,8 @@ plugins {
     id 'de.marcphilipp.nexus-publish' version '0.4.0'
 }
 
+apply from: 'scripts/dependencies.gradle'
+
 checkstyle {
     configFile file('config/checkstyle/checkstyle.xml')
 }
@@ -71,52 +73,48 @@ subprojects {
         mavenLocal()
         mavenCentral()
         jcenter()
-
         maven {
+            /* Sonatype Snapshots */
             url = 'https://oss.sonatype.org/content/repositories/snapshots'
         }
-
         maven {
+            /* ViaVersion, used for adventure */
             url = 'https://repo.viaversion.com/'
         }
-
         maven {
+            /* Velocity, used for cloud-velocity */
             url = 'https://repo.velocitypowered.com/snapshots/'
         }
-
         maven {
+            /* The Minecraft repository, used for cloud-brigadier */
             url = 'https://libraries.minecraft.net/'
         }
-
         maven {
+            /* The current Sponge repository */
             url = 'https://repo.spongepowered.org/maven'
         }
-
         maven {
+            /* The Spigot repository, used for cloud-bukkit */
             url = 'https://hub.spigotmc.org/nexus/content/repositories/snapshots/'
         }
-
         maven {
+            /* The paper repository, used for cloud-paper */
             url = 'https://papermc.io/repo/repository/maven-public/'
         }
-
-        maven {
-            url = 'https://libraries.minecraft.net'
-        }
-
         maven {
+            /* The NukkitX repository, used for cloud-cloudburst */
             url = 'https://repo.nukkitx.com/maven-snapshots'
         }
-
         maven {
+            /* JitPack, used for random dependencies */
             url = 'https://jitpack.io'
         }
     }
 
     dependencies {
-        compileOnly 'org.checkerframework:checker-qual:3.7.0'
-        api 'io.leangen.geantyref:geantyref:1.3.11'
-        testImplementation 'org.junit.jupiter:junit-jupiter-engine:5.7.0'
+        compileOnly "org.checkerframework:checker-qual:${vers['checker-qual']}"
+        api "io.leangen.geantyref:geantyref:${vers['geantyref']}"
+        testImplementation "org.junit.jupiter:junit-jupiter-engine:${vers['jupiter-engine']}"
     }
 
     nexusPublishing {