chore: prepare RC-1 (#783)

### Motivation
RC-1 is on its way and we need to prepare everything for it.

### Modifications
Added a new `beta` branch in the launcher.cnl which is the new default.

### Results
We are getting closer to RC-1

Author: 0utplay

Jenkinsfile

@@ -17,7 +17,7 @@
 object Versions {
 
   // internal versions
-  const val cloudNet = "4.0.0-SNAPSHOT"
+  const val cloudNet = "4.0.0-RC1"
   const val cloudNetCodeName = "Blizzard"
 
   // external tools

build-extensions/src/main/kotlin/Versions.kt

@@ -34,10 +34,13 @@ var cloudnet.updateRepo CloudNetService/launchermeta
 # branches are:
 #  - 'release':     Always contains the latest release version. This is the best version you can choose for a network
 #                   running in production.
+#  - 'beta':        Contains the newest features of the system which are partly tested and out for community testing.
+#                   These features might still be broken but shouldn't break your network. Changes to these features are
+#                   still possible and your configuration you did might break when the feature gets out of testing.
 #  - 'nightly':     All bleeding edge but newest features of the system. DO NOT USE IN PRODUCTION. Your network is not
 #                   safe and something might break. Good for testing purposes or developers which want to use the latest
 #                   features available. (Use this branch at your own risk!)
-var cloudnet.updateBranch release
+var cloudnet.updateBranch beta
 
 # available default log levels: OFF, SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST, ALL
 # each level includes all messages for levels lower than itself (in the above list: left to right) too

launcher/java17/src/main/resources/launcher.cnl

@@ -3,7 +3,7 @@
   "info" : {
     "description" : "CloudNet's rest API version 2 is the next generation in CloudNet's rest history. It has\ndefinitely more opportunities than the previous version of it and provides\na lot of methods to manage and control the CloudNet node and cluster behaviour.\n\nThe API is based on http/https requests and mostly JSON responses. You need\nto send your session bearer token when you make a request. The token can be\nobtained by sending a request to the /auth route. Most of the routes require\nan authentication and a permission which must be set to access the endpoint.\n\nAll the responses contain a `success` boolean (if they are JSON responses) giving\ninformation whether or not the request was handled successfully. If that boolean is\n`false` an extra `reason` field is appended to the JSON entity defining the cause\nof the failure.\n\nEvery rest rout is fixed to a version number and every call must contain one.\nThe latest one is 2. The latest stable endpoint base URL is\n`http(s)://{host}:{port}/api/v2/`. Host and port is the one defined in your\nCloudNet's node config.json `httpListeners` section. If you want to use https\nyou have to configure the web SSL settings in the same file.\n",
     "version" : "2",
-    "title" : "CloudNet v3",
+    "title" : "CloudNet",
     "contact" : {
       "url" : "https://cloudnetservice.eu",
       "name" : "CloudNetService"