Add a muse configuration file (#5557)

* Add a muse configuration file

A muse configuration and file is necessary to educate the MuseDev CI
system on how to build Skywalking.

* Exclude .muse/* files from license check

.muse/config.toml

@@ -0,0 +1,2 @@
+jdk11 = true
+setup = ".muse/setup.sh"

.muse/setup.sh

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+git submodule update --init --recursive

pom.xml

@@ -451,6 +451,7 @@
                         <exclude>**/.git/**</exclude>
 
                         <!-- CI files -->
+                        <exclude>**/.muse/**</exclude>
                         <exclude>**/.travis.yml</exclude>
 
                         <!-- GitHub files -->