🧹 Clean up the gradle build scripts a little

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

cloud-minecraft/cloud-brigadier/build.gradle

@@ -1,5 +1,5 @@
 dependencies {
     implementation project(':cloud-core')
     /* Needs to be provided by the platform */
-    compileOnly 'com.mojang:brigadier:1.0.17'
+    compileOnly "com.mojang:brigadier:${vers['brigadier']}"
 }

cloud-minecraft/cloud-bukkit/build.gradle

@@ -2,6 +2,6 @@ dependencies {
     api project(':cloud-core')
     api project(':cloud-brigadier')
     api project(':cloud-tasks')
-    compileOnly 'org.bukkit:bukkit:1.13.2-R0.1-SNAPSHOT'
-    compileOnly 'me.lucko:commodore:1.9'
+    compileOnly "org.bukkit:bukkit:${vers['bukkit']}"
+    compileOnly "me.lucko:commodore:${vers['commodore']}"
 }

cloud-minecraft/cloud-bungee/build.gradle

@@ -1,4 +1,4 @@
 dependencies {
     api project(':cloud-core')
-    compileOnly 'net.md-5:bungeecord-api:1.8-SNAPSHOT'
+    compileOnly "net.md-5:bungeecord-api:${vers['bungeecord']}"
 }

cloud-minecraft/cloud-cloudburst/build.gradle

@@ -1,4 +1,4 @@
 dependencies {
     api project(':cloud-core')
-    compileOnly 'org.cloudburstmc:cloudburst-server:1.0.0-SNAPSHOT'
+    compileOnly "org.cloudburstmc:cloudburst-server:${vers['cloudburst']}"
 }

cloud-minecraft/cloud-minecraft-extras/build.gradle

@@ -1,4 +1,4 @@
 dependencies {
     api project(':cloud-core')
-    api 'net.kyori:adventure-api:4.1.1'
+    api "net.kyori:adventure-api:${vers['adventure-api']}"
 }

cloud-minecraft/cloud-paper/build.gradle

@@ -1,5 +1,5 @@
 dependencies {
     api project(':cloud-bukkit')
-    compileOnly 'com.destroystokyo.paper:paper-api:1.15.2-R0.1-SNAPSHOT'
-    compileOnly 'com.destroystokyo.paper:paper-mojangapi:1.15.2-R0.1-SNAPSHOT'
+    compileOnly "com.destroystokyo.paper:paper-api:${vers['paper-api']}"
+    compileOnly "com.destroystokyo.paper:paper-mojangapi:${vers['paper-api']}"
 }

cloud-minecraft/cloud-velocity/build.gradle

@@ -1,5 +1,5 @@
 dependencies {
     api project(':cloud-core')
     api project(':cloud-brigadier')
-    compileOnly 'com.velocitypowered:velocity-api:1.1.0-SNAPSHOT'
+    compileOnly "com.velocitypowered:velocity-api:${vers['velocity-api']}"
 }